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• 1. [Article] Stream temperatures, riparian vegetation, and channel morphology in the Upper Grande Ronde River Watershed, Oregon

  The Upper Grande Ronde River Watershed in northeastern Oregon is considered important habitat for threatened stocks of chinook salmon (Oncorhynchus tshawytscha). Documented reductions in channel complexity ...

  Citation × Citation Citation Abstract Copy Title: Stream temperatures, riparian vegetation, and channel morphology in the Upper Grande Ronde River Watershed, Oregon Author: Bohle, Todd S. The Upper Grande Ronde River Watershed in northeastern Oregon is considered important habitat for threatened stocks of chinook salmon (Oncorhynchus tshawytscha). Documented reductions in channel complexity and riparian vegetation within the watershed have increased concern over loss of viable habitat. An important component of salmonid habitat is stream temperature during critical summer periods. In general, annual maximum stream temperatures and diurnal fluctuations in the Upper Grande Ronde River were found to reflect local reach characteristics, position in the drainage, and large-scale changes in valley shape. Stream temperatures on the Grande Ronde River at a distance of 71 km from the watershed divide exceeded 14°C, the "upper preferred temperature" for chinook salmon, more than 90% of time in July of 1991 and in July and August of 1992. While the occurrence of temperatures above 14°C were less common in the headwaters of the Grande Ronde River, downstream of a large meadow (i.e., Vey Meadow) (29 km from the divide) 14°C was exceeded at least 60% of the time during the same three month period. Seven-day maximum stream temperatures on the Upper Grande Ronde River ranged between 17.9°C and 26.6°C in 1991 and between 19.1°C and 26.7°C in 1992. Diel fluctuations on the mainstem were greatest immediately below Vey Meadow (about 12°C) but tended to stabilize at approximately 8°C at distances of over 49 km from the divide. Maximum stream temperatures in tributaries of the Upper Grande Ronde River varied by as much as 11°C (during 1992), reflecting large differences in stream cover, aspect, and flow. The timing of annual maximums seemed to be strongly linked to aspect during 1992. In addition, the high-elevation, forested tributaries had annual maximum stream temperatures and diel fluctuations which were 3°C lower than those associated with more open, low-elevation sites. Relationships between stream temperatures, riparian vegetation, and channel morphology characteristics were evaluated for 11 tributary reaches. Differences in stream cover, average flow velocity, bankfull depth and percent undercut bank were found to be significantly (p <0.1) related to maximum stream temperatures and/or average August diel fluctuations based on linear regression models. A stream temperature prediction model (i.e., TEMP-86) was found to be an accurate predictor of average hourly strew temperatures through short 250-m long reaches. An average WSTAT (a measure of model accuracy) of -0.18°C was calculated based on 11 reaches though two reaches led to consistent over- and under-predictions of downstream temperatures. A series of temperature simulations using TEMP-86 and combinations of wetted width and percent stream cover suggest that lower maximum daily stream temperatures would be observed through altered reaches if concurrent changes in both parameters occurred. Title: Stream temperatures, riparian vegetation, and channel morphology in the Upper Grande Ronde River Watershed, Oregon Author: Bohle, Todd S. The Upper Grande Ronde River Watershed in northeastern Oregon is considered important habitat for threatened stocks of chinook salmon (Oncorhynchus tshawytscha). Documented reductions in channel complexity and riparian vegetation within the watershed have increased concern over loss of viable habitat. An important component of salmonid habitat is stream temperature during critical summer periods. In general, annual maximum stream temperatures and diurnal fluctuations in the Upper Grande Ronde River were found to reflect local reach characteristics, position in the drainage, and large-scale changes in valley shape. Stream temperatures on the Grande Ronde River at a distance of 71 km from the watershed divide exceeded 14°C, the "upper preferred temperature" for chinook salmon, more than 90% of time in July of 1991 and in July and August of 1992. While the occurrence of temperatures above 14°C were less common in the headwaters of the Grande Ronde River, downstream of a large meadow (i.e., Vey Meadow) (29 km from the divide) 14°C was exceeded at least 60% of the time during the same three month period. Seven-day maximum stream temperatures on the Upper Grande Ronde River ranged between 17.9°C and 26.6°C in 1991 and between 19.1°C and 26.7°C in 1992. Diel fluctuations on the mainstem were greatest immediately below Vey Meadow (about 12°C) but tended to stabilize at approximately 8°C at distances of over 49 km from the divide. Maximum stream temperatures in tributaries of the Upper Grande Ronde River varied by as much as 11°C (during 1992), reflecting large differences in stream cover, aspect, and flow. The timing of annual maximums seemed to be strongly linked to aspect during 1992. In addition, the high-elevation, forested tributaries had annual maximum stream temperatures and diel fluctuations which were 3°C lower than those associated with more open, low-elevation sites. Relationships between stream temperatures, riparian vegetation, and channel morphology characteristics were evaluated for 11 tributary reaches. Differences in stream cover, average flow velocity, bankfull depth and percent undercut bank were found to be significantly (p <0.1) related to maximum stream temperatures and/or average August diel fluctuations based on linear regression models. A stream temperature prediction model (i.e., TEMP-86) was found to be an accurate predictor of average hourly strew temperatures through short 250-m long reaches. An average WSTAT (a measure of model accuracy) of -0.18°C was calculated based on 11 reaches though two reaches led to consistent over- and under-predictions of downstream temperatures. A series of temperature simulations using TEMP-86 and combinations of wetted width and percent stream cover suggest that lower maximum daily stream temperatures would be observed through altered reaches if concurrent changes in both parameters occurred. Close

• 2. [Article] An economic comparison of alternative bluegrass residue management practices in Oregon's Grande Ronde Valley

  Published February 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/cata...

  Citation × Citation Citation Abstract Copy Title: An economic comparison of alternative bluegrass residue management practices in Oregon's Grande Ronde Valley Author: Walenta, Darrin L., 1968-, Gow, Laura R., Diebel, Penelope L., 1961-, Oregon State University. Agricultural Experiment Station Published February 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: An economic comparison of alternative bluegrass residue management practices in Oregon's Grande Ronde Valley Author: Walenta, Darrin L., 1968-, Gow, Laura R., Diebel, Penelope L., 1961-, Oregon State University. Agricultural Experiment Station Published February 2009. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 3. [Article] Evaluation and cost analysis of alternative residue management methods for Kentucky bluegrass seed production in the Grande Ronde Valley

  The production of high quality grass seed is important to the agricultural economy of the Grande Ronde Valley (GRV) of eastern Oregon. The predominate grass seed crops grown in the area are Kentucky bluegrass ...

  Citation × Citation Citation Abstract Copy Title: Evaluation and cost analysis of alternative residue management methods for Kentucky bluegrass seed production in the Grande Ronde Valley Author: Walenta, Darrin L., 1968-, Diebel, Penelope L., 1961-, Gow, Laura R., Kiemnec, Gary L. The production of high quality grass seed is important to the agricultural economy of the Grande Ronde Valley (GRV) of eastern Oregon. The predominate grass seed crops grown in the area are Kentucky bluegrass and fine fescues. Historically, open-field burning has been an effective, economical means by which to remove residue and maintain seed yield and quality. The continued concern for air quality and public health have led to the adoption of alternative residue management methods that place less reliance on open-field burning of full straw residue loads. Title: Evaluation and cost analysis of alternative residue management methods for Kentucky bluegrass seed production in the Grande Ronde Valley Author: Walenta, Darrin L., 1968-, Diebel, Penelope L., 1961-, Gow, Laura R., Kiemnec, Gary L. The production of high quality grass seed is important to the agricultural economy of the Grande Ronde Valley (GRV) of eastern Oregon. The predominate grass seed crops grown in the area are Kentucky bluegrass and fine fescues. Historically, open-field burning has been an effective, economical means by which to remove residue and maintain seed yield and quality. The continued concern for air quality and public health have led to the adoption of alternative residue management methods that place less reliance on open-field burning of full straw residue loads. Close

• 4. [Article] From the Willamette to the Coast Range

  Citation × Citation Citation Abstract Copy Title: From the Willamette to the Coast Range Author: Adams, James Davis (J.D.) Title: From the Willamette to the Coast Range Author: Adams, James Davis (J.D.) Close

• 5. [Article] Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon

  Citation × Citation Citation Abstract Copy Title: Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon Author: Otting, Nicholas J. Title: Ecological characteristics of montane floodplain plant communities in the Upper Grande Ronde basin, Oregon Author: Otting, Nicholas J. Close

• 6. [Article] Historical changes in anadromous fish habitat in the Upper Grande Ronde River, Oregon, 1941-1990

  The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream ...

  Citation × Citation Citation Abstract Copy Title: Historical changes in anadromous fish habitat in the Upper Grande Ronde River, Oregon, 1941-1990 Author: McIntosh, Bruce A. The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream habitat conditions for anadromous salmonids (Oncorhynchus spp.) throughout the Columbia River Basin. The survey systematically inventoried 158 km of streams within the 3000 km2 watershed. Stream habitat was degraded from land-use activities (riparian timber harvest, splash dams, stream channelization, livestock grazing, and mining) prior to the 1941 survey. A 1990 resurvey determined how stream habitat conditions had continued to change. The historical survey and the 1990 resurvey inventoried streams according to pool and substrate characteristics. Pools were classified by size and depth criteria, while substrate was divided into size-classes. Losses in total pools/km (> 20m2 area and > 0.5 m depth) ranged from 43 to 83% (mean = 65%, 12.2 to 4.31km), while the loss in large pools/km (> 20m2 and > 1.0 m depth) ranged from 20 to 89% (mean = 68%, 6.2 to 2.0/1cm) for individual streams. The loss of variability in pool frequencies from 1941 to 1990 (total pools/km a2 = 43.9 to 2.8, large pools/km a2 = 23.2 to 3.2) demonstrates that stream channels have become less diverse. Classifying streams by reach types indicated that the decline in pool frequencies was not significantly related to geomorphic constraints. Substrate composition appears to have shifted toward smaller size-classes, with an increase in fine sediments (< 6mm) in the headwaters. Livestock grazing declined 78% (229,000 to 51,000 aum) from 1911 to 1990, while annual timber harvest increased 172% (36 to 98 mmbf) from the pre-survey period (1896-1940) to the post-survey period (1940-1990). Road densities have increased concurrent with timber harvest, currently averaging 4 miles/mile2. Base discharge has increased 51% (18.5 to 28.0 cfs), while there has been a 27% decrease in annual precipitation (22.0" to 16.0") and snowpack (April 1 water equivalent) (15.0" to 10.5") from 1941 to 1990. In an era of presumably improving management (1941-1990), large-scale losses in the fish habitat necessary for the continued viability of resident and anadromous fish populations continued to occur. Title: Historical changes in anadromous fish habitat in the Upper Grande Ronde River, Oregon, 1941-1990 Author: McIntosh, Bruce A. The U.S. Bureau of Fisheries (now National Marine Fisheries Service) conducted stream habitat surveys in the Upper Grande Ronde River Basin in 1941. This survey was part of an extensive inventory of stream habitat conditions for anadromous salmonids (Oncorhynchus spp.) throughout the Columbia River Basin. The survey systematically inventoried 158 km of streams within the 3000 km2 watershed. Stream habitat was degraded from land-use activities (riparian timber harvest, splash dams, stream channelization, livestock grazing, and mining) prior to the 1941 survey. A 1990 resurvey determined how stream habitat conditions had continued to change. The historical survey and the 1990 resurvey inventoried streams according to pool and substrate characteristics. Pools were classified by size and depth criteria, while substrate was divided into size-classes. Losses in total pools/km (> 20m2 area and > 0.5 m depth) ranged from 43 to 83% (mean = 65%, 12.2 to 4.31km), while the loss in large pools/km (> 20m2 and > 1.0 m depth) ranged from 20 to 89% (mean = 68%, 6.2 to 2.0/1cm) for individual streams. The loss of variability in pool frequencies from 1941 to 1990 (total pools/km a2 = 43.9 to 2.8, large pools/km a2 = 23.2 to 3.2) demonstrates that stream channels have become less diverse. Classifying streams by reach types indicated that the decline in pool frequencies was not significantly related to geomorphic constraints. Substrate composition appears to have shifted toward smaller size-classes, with an increase in fine sediments (< 6mm) in the headwaters. Livestock grazing declined 78% (229,000 to 51,000 aum) from 1911 to 1990, while annual timber harvest increased 172% (36 to 98 mmbf) from the pre-survey period (1896-1940) to the post-survey period (1940-1990). Road densities have increased concurrent with timber harvest, currently averaging 4 miles/mile2. Base discharge has increased 51% (18.5 to 28.0 cfs), while there has been a 27% decrease in annual precipitation (22.0" to 16.0") and snowpack (April 1 water equivalent) (15.0" to 10.5") from 1941 to 1990. In an era of presumably improving management (1941-1990), large-scale losses in the fish habitat necessary for the continued viability of resident and anadromous fish populations continued to occur. Close

• 7. [Article] Basin level ecological regions of the upper Grande Ronde River

  Citation × Citation Citation Abstract Copy Title: Basin level ecological regions of the upper Grande Ronde River Author: Thiele, Sandra Anne Title: Basin level ecological regions of the upper Grande Ronde River Author: Thiele, Sandra Anne Close

• 8. [Article] Year 2000 Timber Sales - Confederated Tribes on Grand Ronde : Biological Opinion

  The Natural Resources Division (NRD) of the Confederated Tribes of Grand Ronde (CTGR), in cooperation with the Bureau of Indian Affairs (BIA), proposes the regeneration harvest and commercial thinning ...

  Citation × Citation Citation Abstract Copy Title: Year 2000 Timber Sales - Confederated Tribes on Grand Ronde : Biological Opinion The Natural Resources Division (NRD) of the Confederated Tribes of Grand Ronde (CTGR), in cooperation with the Bureau of Indian Affairs (BIA), proposes the regeneration harvest and commercial thinning of four timber sales on the Reservation of The Confederated Tribes of Grand Ronde (CTGR). The CTGR has a 20-year management agreement with the BIA. For the purposes of this consultation the BIA is the action agency. The proposed timber harvest units are in the South Yamhill River subbasin, which supports two species listed by the National Marine Fisheries Service (NMFS) as threatened under the Federal Endangered Species Act (ESA). Upper Willamette River (UWR) chinook salmon (Oncorhynchus tshawytscha) were listed as threatened under the ESA on May 24, 1999. Upper Willamette River (UWR) steelhead (Oncorhynchus mykiss) were listed as threatened under the ESA on March 25, 1999. Critical habitat for both of these species was designated on February 16, 2000 (effective on March 17, 2000). According to the BA, UWR chinook do not currently reside in the action area and there is no recorded data indicating they were present historically. The nearest known occurrence of UWR chinook is near the confluence of Salt creek and the South Yamhill River, over 40 stream miles from the Reservation. Juvenile UWR steelhead reside within the action area and are known to occur in streams on the reservation. Based on the presence of juveniles, CTGR staff suspect that adult UWR steelhead spawn in streams on the Reservation, although little spawning survey work has been done. Title: Year 2000 Timber Sales - Confederated Tribes on Grand Ronde : Biological Opinion The Natural Resources Division (NRD) of the Confederated Tribes of Grand Ronde (CTGR), in cooperation with the Bureau of Indian Affairs (BIA), proposes the regeneration harvest and commercial thinning of four timber sales on the Reservation of The Confederated Tribes of Grand Ronde (CTGR). The CTGR has a 20-year management agreement with the BIA. For the purposes of this consultation the BIA is the action agency. The proposed timber harvest units are in the South Yamhill River subbasin, which supports two species listed by the National Marine Fisheries Service (NMFS) as threatened under the Federal Endangered Species Act (ESA). Upper Willamette River (UWR) chinook salmon (Oncorhynchus tshawytscha) were listed as threatened under the ESA on May 24, 1999. Upper Willamette River (UWR) steelhead (Oncorhynchus mykiss) were listed as threatened under the ESA on March 25, 1999. Critical habitat for both of these species was designated on February 16, 2000 (effective on March 17, 2000). According to the BA, UWR chinook do not currently reside in the action area and there is no recorded data indicating they were present historically. The nearest known occurrence of UWR chinook is near the confluence of Salt creek and the South Yamhill River, over 40 stream miles from the Reservation. Juvenile UWR steelhead reside within the action area and are known to occur in streams on the reservation. Based on the presence of juveniles, CTGR staff suspect that adult UWR steelhead spawn in streams on the Reservation, although little spawning survey work has been done. Close

• 9. [Article] Strontium isotopic and trace element geochemistry of the Saddle Mountains and Grande Rondé basalts of the Columbia River basalt group

  Citation × Citation Citation Abstract Copy Title: Strontium isotopic and trace element geochemistry of the Saddle Mountains and Grande Rondé basalts of the Columbia River basalt group Author: Nelson, Dennis O. Title: Strontium isotopic and trace element geochemistry of the Saddle Mountains and Grande Rondé basalts of the Columbia River basalt group Author: Nelson, Dennis O. Close

• 10. [Article] The geology of the Elk Mountain-Porter Ridge area, Clatsop County, northwest Oregon

  Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); ...

  Citation × Citation Citation Abstract Copy Title: The geology of the Elk Mountain-Porter Ridge area, Clatsop County, northwest Oregon Author: Goalen, Jeffrey Scott Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt, and Frenchman Springs Member of the Wanapum Basalt, both of the Columbia River Basalt Group. Also, areally limited, unnamed sedimentary strata interbedded between flows of the Columbia River Basalt Group crop out in the study area. Quaternary deposits consist of alluvium, colluvium, and landslide debris. Rhythmically-bedded, foram-bearing, carbonaceous to micaceous mudstone and graded, fine-grained, feldspathic turbidite sandstone are the dominant lithologies of the upper Eocene (Refugian) Sager Creek formation. Plane-laminae and climbing ripple-laminae typical of Bouma b,c, and d intervals are common in the thin turbidite sandstone beds. Contemporaneous, rare, thick, sandstones may represent submarine feeder channels that supplied the more widespread, thinly-bedded overbank turbidite sandstones. Foraminiferal paleobathymetry indicates that deposition was in bathyal water depths. Sager Creek deposition was followed by a regression or offlap of the late Eocene to early Oligocene (Refugian) sea as indicated by the molluscan fossils and thick, bioturbated sandstone of the predominantly shallow-marine Pittsburg Bluff Formation. The lower part of the formation consists of outer shelf, glauconitic, fossiliferous sandstone and subordinate mudstone. Higher in the section are middle-shelf, fine-grained, bioturbated, tuffaceous, arkosic sandstones. These sandstones contain minor glauconite, wave- and storm-generated molluscan shell hash beds, carbonized wood fragments, and calcareous concretions. Deposition occurred in 20 - 50 m open-marine shelf water depths; however, the depositional environment may have shallowed to a bay-like setting (Moore, 1982, written communication). The upper part of the unit consists of thin- to medium-bedded, carbonaceous siltstone and mudstone with minor ashfall tuffs. Therefore, deposition of the Pittsburg Bluff Formation occurred as a shallowing-upward, then deepening depositional episode, punctuated by contemporaneous, intermittent eruption of nearby calc-alkaline western Cascade volcanoes. The deep-marine Oligocene to lower Miocene (Zemorrian to Saucesian) Northrup Creek formation is predominantly composed of thinly-laminated mudstone interbedded with thin, very fine-grained, graded, micaceous arkosic sandstone. Bouma c-d-e and a-b-e sequences are common in the turbidite sandstone; Bouma a-e intervals occur locally in sandstone/mudstone couplets. Paleocurrent indicators suggest that the predominant transport direction of these turbidite deposits was northeast to southwest. Abraded, carbonaceous plant debris and mica are abundant in the sandstone laminations. The upper part of the formation consists of thick, mollusk-bearing, moderately- to well-sorted, arkosic sandstone and minor polymict grit beds. A shallowing-upward, high-energy, shallow-marine shelf environment of deposition is indicated for the upper part of the formation. Contemporaneous with shelf and slope deposition of the Sager Creek, Pittsburg Bluff and Northrup Creek formations, the deep-water late Eocene to early Miocene Smuggler Cove formation was deposited as a distal or lateral correlative in a low-energy, outer shelf to slope setting. This foram-bearing unit consists of thick, bioturbated, bathyal, tuffaceous mudstone and siltstone with minor thin- to thick-bedded ashfall and current-reworked tuff. A marine onlap is indicated by the conformable relationship between the upper sandstone unit of the Northrup Creek formation and the overlying Smuggler Cove formation in the eastern part of the thesis area. The overlying lower to middle Miocene Astoria Formation contains two members in the thesis area: a high-energy, shallow shelf, fine- to medium-grained, fossiliferous, micaceous arkosic sandstone (Wickiup Mountain member), and an overlying, thinly-laminated, deepmarine mudstone (Cannon Beach member). Diatom floras indicate that a thermal "oceanographic irregularity" (water warmer than normal) may have occurred during deposition of the Cannon Beach member. At least six, and possibly eight, flows of the middle Miocene Grande Ronde Basalt (Columbia River Basalt Group) are present in the thesis area. Individual flows have been ascribed to the (N1?), R2, and N2 magnetozones. Geochemically, the flows consist of low MgO high Ti02, low MgO low Ti02, and high MgO subtypes. These subaerial to submarine flows are correlated to Mangan and others (1986) chemical subtypes 2D, 5C, 5A, and 4A of the Columbia Plateau-derived Grande Ronde Basalt of eastern Washington and eastern Oregon. The correlations are based on similarity of age, major element chemistry, stratigraphic position, and magnetic polarity. Field evidence suggests that thick, submarine pillow and breccia complexes generated sufficient pressure to autoinvasively inject into the Eocene to middle Miocene sedimentary strata of the Plympton/Porter ridge and Elk Mountain areas. This process apparently formed many randomly-oriented dike- and sill-like intrusions in the western part of the thesis area. However, in the eastern and central parts of the thesis area, three sub-parallel dikes (the Northrup, Beneke, and Fishhawk Falls dikes) extend along linear trends for tens of kilometers. This suggests that their emplacement was, in part, influenced by earlier or contemporaneous regional tectonism. At least two, and as many as five, flows of the Frenchman Springs Member of the Wanapum Basalt occur in the thesis area: one to two abundantly plagioclase-phyric Basalt of Ginkgo flow(s), and one to three Basalt of Sand Hollow flows (terminology after Beeson and Tolan, 1985). These flows consist of subaqueous pillow palagonite breccia and vesicular, columnar-jointed, subaerial basalt. No Frenchman Springs flows are invasive in the thesis area. Local middle Miocene sedimentary interbeds between flows of Grande Ronde and Frenchman Springs Basalt are lithologically and sedimentologically diverse. Common lithologies are fine- to mediumgrained, arkosic sandstone, coarse-grained basaltic sandstone, and structureless mudstone. Depositional environments represented by these strata are fluvial, marginal-marine, and shallow-marine. Thicknesses of individual interbeds range from 0.2 to 50 m. The thesis area is located on the northwest flank of the Oregon Coast Range anticline, adjacent to the Nehalem Arch. Large-scale northeast-trending oblique to strike-slip left-lateral faults coupled with northwest-trending oblique to strike-slip right-lateral faults dominate the structure of the area. These faults may have formed as conjugate shears (Riedel shear) caused by north-south compressive stress related to the oblique subduction of the Juan de Fuca Plate beneath the North American Plate. Five episodes of deformation are suggested by faults, dike orientations, unconformities, and other geological relationships within the thesis area: a late Eocene north-south compressional episode, an early Oligocene to early Miocene uplift, a middle Miocene northwest-southeast extensional episode, a post-middle Miocene to Pliocene (?) north-south compressional episode, and a north-south extensional event that occurred between the post-middle Miocene and Recent. Although crushed rock (for road and revetment construction) is currently the primary mineral resource within the thesis area, several potential fault traps on this northwest flank of the Nehalem Arch may contain significant reserves of natural gas. This conclusion is based upon field, laboratory, and subsurface (well) data. The Clark and Wilson sandstone of the middle to late Eocene Cowlitz Formation, the producing unit at the nearby Mist gas field, represents the most attractive target horizon. Additionally, the porous and permeable upper sandstone unit of the Northrup Creek formation could contain shallow hydrocarbon reserves beneath the northern part of the area. Title: The geology of the Elk Mountain-Porter Ridge area, Clatsop County, northwest Oregon Author: Goalen, Jeffrey Scott Eight Tertiary sedimentary and volcanic units crop out in the thesis area. From oldest to youngest they are the: Sager Creek formation (informal); Pittsburg Bluff Formation; Northrup Creek formation (informal); Smuggler Cove formation (informal); Wickiup Mountain and Cannon Beach members (both informal) of the Astoria Formation; the Grande Ronde Basalt, and Frenchman Springs Member of the Wanapum Basalt, both of the Columbia River Basalt Group. Also, areally limited, unnamed sedimentary strata interbedded between flows of the Columbia River Basalt Group crop out in the study area. Quaternary deposits consist of alluvium, colluvium, and landslide debris. Rhythmically-bedded, foram-bearing, carbonaceous to micaceous mudstone and graded, fine-grained, feldspathic turbidite sandstone are the dominant lithologies of the upper Eocene (Refugian) Sager Creek formation. Plane-laminae and climbing ripple-laminae typical of Bouma b,c, and d intervals are common in the thin turbidite sandstone beds. Contemporaneous, rare, thick, sandstones may represent submarine feeder channels that supplied the more widespread, thinly-bedded overbank turbidite sandstones. Foraminiferal paleobathymetry indicates that deposition was in bathyal water depths. Sager Creek deposition was followed by a regression or offlap of the late Eocene to early Oligocene (Refugian) sea as indicated by the molluscan fossils and thick, bioturbated sandstone of the predominantly shallow-marine Pittsburg Bluff Formation. The lower part of the formation consists of outer shelf, glauconitic, fossiliferous sandstone and subordinate mudstone. Higher in the section are middle-shelf, fine-grained, bioturbated, tuffaceous, arkosic sandstones. These sandstones contain minor glauconite, wave- and storm-generated molluscan shell hash beds, carbonized wood fragments, and calcareous concretions. Deposition occurred in 20 - 50 m open-marine shelf water depths; however, the depositional environment may have shallowed to a bay-like setting (Moore, 1982, written communication). The upper part of the unit consists of thin- to medium-bedded, carbonaceous siltstone and mudstone with minor ashfall tuffs. Therefore, deposition of the Pittsburg Bluff Formation occurred as a shallowing-upward, then deepening depositional episode, punctuated by contemporaneous, intermittent eruption of nearby calc-alkaline western Cascade volcanoes. The deep-marine Oligocene to lower Miocene (Zemorrian to Saucesian) Northrup Creek formation is predominantly composed of thinly-laminated mudstone interbedded with thin, very fine-grained, graded, micaceous arkosic sandstone. Bouma c-d-e and a-b-e sequences are common in the turbidite sandstone; Bouma a-e intervals occur locally in sandstone/mudstone couplets. Paleocurrent indicators suggest that the predominant transport direction of these turbidite deposits was northeast to southwest. Abraded, carbonaceous plant debris and mica are abundant in the sandstone laminations. The upper part of the formation consists of thick, mollusk-bearing, moderately- to well-sorted, arkosic sandstone and minor polymict grit beds. A shallowing-upward, high-energy, shallow-marine shelf environment of deposition is indicated for the upper part of the formation. Contemporaneous with shelf and slope deposition of the Sager Creek, Pittsburg Bluff and Northrup Creek formations, the deep-water late Eocene to early Miocene Smuggler Cove formation was deposited as a distal or lateral correlative in a low-energy, outer shelf to slope setting. This foram-bearing unit consists of thick, bioturbated, bathyal, tuffaceous mudstone and siltstone with minor thin- to thick-bedded ashfall and current-reworked tuff. A marine onlap is indicated by the conformable relationship between the upper sandstone unit of the Northrup Creek formation and the overlying Smuggler Cove formation in the eastern part of the thesis area. The overlying lower to middle Miocene Astoria Formation contains two members in the thesis area: a high-energy, shallow shelf, fine- to medium-grained, fossiliferous, micaceous arkosic sandstone (Wickiup Mountain member), and an overlying, thinly-laminated, deepmarine mudstone (Cannon Beach member). Diatom floras indicate that a thermal "oceanographic irregularity" (water warmer than normal) may have occurred during deposition of the Cannon Beach member. At least six, and possibly eight, flows of the middle Miocene Grande Ronde Basalt (Columbia River Basalt Group) are present in the thesis area. Individual flows have been ascribed to the (N1?), R2, and N2 magnetozones. Geochemically, the flows consist of low MgO high Ti02, low MgO low Ti02, and high MgO subtypes. These subaerial to submarine flows are correlated to Mangan and others (1986) chemical subtypes 2D, 5C, 5A, and 4A of the Columbia Plateau-derived Grande Ronde Basalt of eastern Washington and eastern Oregon. The correlations are based on similarity of age, major element chemistry, stratigraphic position, and magnetic polarity. Field evidence suggests that thick, submarine pillow and breccia complexes generated sufficient pressure to autoinvasively inject into the Eocene to middle Miocene sedimentary strata of the Plympton/Porter ridge and Elk Mountain areas. This process apparently formed many randomly-oriented dike- and sill-like intrusions in the western part of the thesis area. However, in the eastern and central parts of the thesis area, three sub-parallel dikes (the Northrup, Beneke, and Fishhawk Falls dikes) extend along linear trends for tens of kilometers. This suggests that their emplacement was, in part, influenced by earlier or contemporaneous regional tectonism. At least two, and as many as five, flows of the Frenchman Springs Member of the Wanapum Basalt occur in the thesis area: one to two abundantly plagioclase-phyric Basalt of Ginkgo flow(s), and one to three Basalt of Sand Hollow flows (terminology after Beeson and Tolan, 1985). These flows consist of subaqueous pillow palagonite breccia and vesicular, columnar-jointed, subaerial basalt. No Frenchman Springs flows are invasive in the thesis area. Local middle Miocene sedimentary interbeds between flows of Grande Ronde and Frenchman Springs Basalt are lithologically and sedimentologically diverse. Common lithologies are fine- to mediumgrained, arkosic sandstone, coarse-grained basaltic sandstone, and structureless mudstone. Depositional environments represented by these strata are fluvial, marginal-marine, and shallow-marine. Thicknesses of individual interbeds range from 0.2 to 50 m. The thesis area is located on the northwest flank of the Oregon Coast Range anticline, adjacent to the Nehalem Arch. Large-scale northeast-trending oblique to strike-slip left-lateral faults coupled with northwest-trending oblique to strike-slip right-lateral faults dominate the structure of the area. These faults may have formed as conjugate shears (Riedel shear) caused by north-south compressive stress related to the oblique subduction of the Juan de Fuca Plate beneath the North American Plate. Five episodes of deformation are suggested by faults, dike orientations, unconformities, and other geological relationships within the thesis area: a late Eocene north-south compressional episode, an early Oligocene to early Miocene uplift, a middle Miocene northwest-southeast extensional episode, a post-middle Miocene to Pliocene (?) north-south compressional episode, and a north-south extensional event that occurred between the post-middle Miocene and Recent. Although crushed rock (for road and revetment construction) is currently the primary mineral resource within the thesis area, several potential fault traps on this northwest flank of the Nehalem Arch may contain significant reserves of natural gas. This conclusion is based upon field, laboratory, and subsurface (well) data. The Clark and Wilson sandstone of the middle to late Eocene Cowlitz Formation, the producing unit at the nearby Mist gas field, represents the most attractive target horizon. Additionally, the porous and permeable upper sandstone unit of the Northrup Creek formation could contain shallow hydrocarbon reserves beneath the northern part of the area. Close

• 11. [Article] Stratigraphy, structure, and natural gas potential of tertiary sedimentary and volcanic units, Clatskanie 7.5 minute quadrangle, Northwest Oregon

  The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom ...

  Citation × Citation Citation Abstract Copy Title: Stratigraphy, structure, and natural gas potential of tertiary sedimentary and volcanic units, Clatskanie 7.5 minute quadrangle, Northwest Oregon Author: Eriksson, Andrew The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom and molluscan fossil identifications, with subsurface geophysical data and petrographic and geochemical analyses. The stratigraphy of the study area consists of two Tertiary volcanic units (Grays River Volcanics and Columbia River Basalt Group) and four sedimentary units (Cowlitz (subsurface) Keasey, Pittsburg Bluff, and Scappoose formations) that were deposited in the Nehalem forearc basin. The major structure of the area is defined by the oblique-slip Scappoose-Clatskanie fault with both normal and dextral motion. In the east-central part of the study area, this post-Miocene fault zone, formed by a right step over in a right-lateral strike-slip system, created an extensional zone with abundant normal faulting (horsts and grabens). The faulting uplifted an isolated block of middle Eocene Grays River Volcanics subaerial flows against downdropped Miocene Columbia River Basalt in the northwestern part of the map area near the town of Clatskanie along Highway 30. This block was part of a major Grays River Volcanics paleohigh (herein named the Clatskanie High) and forms part of a regional gravity/magnetic high beneath the Columbia river. The Clatskanie High and the Windy Ridge High (subsurfance paleohigh also composed of Grays River Volcanics) in the central to southern part of the study area, restricted deposition and caused onlapping of the Cowlitz, Keasey, and Pittsburg Bluff formations. The Clatskanie High shield volcano defines the northern boundary of the Mist Gas Field. In addition, local unconformities at the base of the Keasey and Pittsburg Bluff formations progressively truncate the Cowlitz C&W sandstone reservoir and upper mudstone seal to the north. The largely unexplored central and northeastern parts of the study area near the Scappoose-Clatskanie fault zone with horst and grabens and stratigraphic pinchouts represent some of the most promising untested exploration plays in the quadrangle. Associated wtih the Clatskanie High are two new (informal) members of the Oligocene Pittsburg Bluff Formation that are defined and mapped by this study. The Conyers Creek member (informal) is a shallow-marine mollusk-bearing pebbly-basaltic litharenite (a poorly sorted nearshore to shoreface sandstone) with an interbedded fossiliferous fine pebble conglomerate of Grays River volcanic clasts. The lens-like nearshore unit was deposited on the margins of the uplifted Grays River basaltic oceanic island and, thus, restricted to an area around the paleohigh. Locally overlying the Conyers Creek member and interbedded with the East Fork member (Pittsburg Bluff Formation) is the Clatskanie Conglomerate member (the second informal member defined by this study). The 180 feet (55 meter) thick member consists of a basal, clast-supported 110 feet (33 meter) thick polymict conglomerate and upper well-consolidated 70 feet (21 meter) think micaceous arkosic sandstone. The Clatskanie Conglomerate is a lens-like fluvial deposit in the northwestern part of the study area, possibly syndepositional and restricted in deposition to the center of a growing syncline. The cobble to boulder sized clasts of quartzite, chert, metamorphics, and andesites/dacites indicate extrabasinal sources such as the Western Cascades arc and continental sources in eastern Oregon, Idaho, Montana, and eastern Washington via an ancestral Columbia River drainage system. The diatom-bearing tuffaceous clayey siltstone of the Keasey Formation and the mollusk-bearing sandy siltstone of the East Fork member (Pittsburg Bluff Formation) formed in continental slope and middle to outer shelf environments. Extensive explosive dacitic eruptions in the nearby Western Cascade arc contributed abundant ash, which washed into the forearc basin. Local Thyosira chemosynthetic pelecypods and calcareous concretionary beds indicate the local presence of either cold methane seeps or a gas hydrate system on the Pittsburg Bluff continental shelf. The Scappoose Formation consists predominantly of a basal basalt and siltstone rip-up conglomerate deposited in an incised valley during a low stand systems tract (LST). The conglomerate is overlain by a diatom-bearing shallow-marine tuffaceous siltstone of a transgressive and highstand systems tracts (TST & HST), and capped by a cross-bedded fluvial lithic arkosic sandstone of a second lowstand systems tract (LST). Chemical analysis of the basal basalt conglomerate clasts indicate that they were derived from erosion of high TiO2R2 Wapshilla Ridge flow unit of the Grande Ronde Basalt (16.5 to 15.6 Ma) of the lower to middle Miocene Columbia River Basalt Group. The Scappoose Formation also includes thin fluvial and lacustrine sandstones and tuffs interbedded with Columbia River Basalt flows. Capping these Tertiary units are three units of low-MgO Grande Ronde Basalt of the Columbia River Basalt Group. These include 1-2 basal aphyric flow(s) of the high-TiO2R2 Wapshilla Ridge flow unit, at least six flows (some invasive) of the R2 low-TiO2 Grouse Creek flow unit, and the upper sparsely glomerophyric flows of N2 Winter Water flow unit. The structural history of the region is characterized by two major tectonic events. A late Eocene extensional period prior to deposition of the Keasey Formation created normal faulting (horsts and grabens) throughout the Cowlitz Formation. These faults formed most of the structural traps in the Mist Gas Field including those drilled by producing wells in the southern part of the quadrangle near the Windy Ridge High. The post-Miocene episode was dominated by wrench fault tectonics that manifested as strike-slip oblique-slip motion on dominant northwest-trending and subordinate northeast-trending faults in the Columbia River Basalt Group flows. Title: Stratigraphy, structure, and natural gas potential of tertiary sedimentary and volcanic units, Clatskanie 7.5 minute quadrangle, Northwest Oregon Author: Eriksson, Andrew The geology and natural gas potential of the Clatskanie 7.5-minute quadrangle in Columbia County, Oregon was studied utilizing a combination of geologic mapping, measuring of stratigraphic sections, diatom and molluscan fossil identifications, with subsurface geophysical data and petrographic and geochemical analyses. The stratigraphy of the study area consists of two Tertiary volcanic units (Grays River Volcanics and Columbia River Basalt Group) and four sedimentary units (Cowlitz (subsurface) Keasey, Pittsburg Bluff, and Scappoose formations) that were deposited in the Nehalem forearc basin. The major structure of the area is defined by the oblique-slip Scappoose-Clatskanie fault with both normal and dextral motion. In the east-central part of the study area, this post-Miocene fault zone, formed by a right step over in a right-lateral strike-slip system, created an extensional zone with abundant normal faulting (horsts and grabens). The faulting uplifted an isolated block of middle Eocene Grays River Volcanics subaerial flows against downdropped Miocene Columbia River Basalt in the northwestern part of the map area near the town of Clatskanie along Highway 30. This block was part of a major Grays River Volcanics paleohigh (herein named the Clatskanie High) and forms part of a regional gravity/magnetic high beneath the Columbia river. The Clatskanie High and the Windy Ridge High (subsurfance paleohigh also composed of Grays River Volcanics) in the central to southern part of the study area, restricted deposition and caused onlapping of the Cowlitz, Keasey, and Pittsburg Bluff formations. The Clatskanie High shield volcano defines the northern boundary of the Mist Gas Field. In addition, local unconformities at the base of the Keasey and Pittsburg Bluff formations progressively truncate the Cowlitz C&W sandstone reservoir and upper mudstone seal to the north. The largely unexplored central and northeastern parts of the study area near the Scappoose-Clatskanie fault zone with horst and grabens and stratigraphic pinchouts represent some of the most promising untested exploration plays in the quadrangle. Associated wtih the Clatskanie High are two new (informal) members of the Oligocene Pittsburg Bluff Formation that are defined and mapped by this study. The Conyers Creek member (informal) is a shallow-marine mollusk-bearing pebbly-basaltic litharenite (a poorly sorted nearshore to shoreface sandstone) with an interbedded fossiliferous fine pebble conglomerate of Grays River volcanic clasts. The lens-like nearshore unit was deposited on the margins of the uplifted Grays River basaltic oceanic island and, thus, restricted to an area around the paleohigh. Locally overlying the Conyers Creek member and interbedded with the East Fork member (Pittsburg Bluff Formation) is the Clatskanie Conglomerate member (the second informal member defined by this study). The 180 feet (55 meter) thick member consists of a basal, clast-supported 110 feet (33 meter) thick polymict conglomerate and upper well-consolidated 70 feet (21 meter) think micaceous arkosic sandstone. The Clatskanie Conglomerate is a lens-like fluvial deposit in the northwestern part of the study area, possibly syndepositional and restricted in deposition to the center of a growing syncline. The cobble to boulder sized clasts of quartzite, chert, metamorphics, and andesites/dacites indicate extrabasinal sources such as the Western Cascades arc and continental sources in eastern Oregon, Idaho, Montana, and eastern Washington via an ancestral Columbia River drainage system. The diatom-bearing tuffaceous clayey siltstone of the Keasey Formation and the mollusk-bearing sandy siltstone of the East Fork member (Pittsburg Bluff Formation) formed in continental slope and middle to outer shelf environments. Extensive explosive dacitic eruptions in the nearby Western Cascade arc contributed abundant ash, which washed into the forearc basin. Local Thyosira chemosynthetic pelecypods and calcareous concretionary beds indicate the local presence of either cold methane seeps or a gas hydrate system on the Pittsburg Bluff continental shelf. The Scappoose Formation consists predominantly of a basal basalt and siltstone rip-up conglomerate deposited in an incised valley during a low stand systems tract (LST). The conglomerate is overlain by a diatom-bearing shallow-marine tuffaceous siltstone of a transgressive and highstand systems tracts (TST & HST), and capped by a cross-bedded fluvial lithic arkosic sandstone of a second lowstand systems tract (LST). Chemical analysis of the basal basalt conglomerate clasts indicate that they were derived from erosion of high TiO2R2 Wapshilla Ridge flow unit of the Grande Ronde Basalt (16.5 to 15.6 Ma) of the lower to middle Miocene Columbia River Basalt Group. The Scappoose Formation also includes thin fluvial and lacustrine sandstones and tuffs interbedded with Columbia River Basalt flows. Capping these Tertiary units are three units of low-MgO Grande Ronde Basalt of the Columbia River Basalt Group. These include 1-2 basal aphyric flow(s) of the high-TiO2R2 Wapshilla Ridge flow unit, at least six flows (some invasive) of the R2 low-TiO2 Grouse Creek flow unit, and the upper sparsely glomerophyric flows of N2 Winter Water flow unit. The structural history of the region is characterized by two major tectonic events. A late Eocene extensional period prior to deposition of the Keasey Formation created normal faulting (horsts and grabens) throughout the Cowlitz Formation. These faults formed most of the structural traps in the Mist Gas Field including those drilled by producing wells in the southern part of the quadrangle near the Windy Ridge High. The post-Miocene episode was dominated by wrench fault tectonics that manifested as strike-slip oblique-slip motion on dominant northwest-trending and subordinate northeast-trending faults in the Columbia River Basalt Group flows. Close

• 12. [Article] A spatially explicit model for allocating conservation efforts : the Grand Ronde River basin, Oregon

  The spatial and dynamic pattern of landscape changes has a profound effect on the supply of environmental services, including the provision of habitat for fish and wildlife. Spatial heterogeneity is a ...

  Citation × Citation Citation Abstract Copy Title: A spatially explicit model for allocating conservation efforts : the Grand Ronde River basin, Oregon Author: Watanabe, Michio The spatial and dynamic pattern of landscape changes has a profound effect on the supply of environmental services, including the provision of habitat for fish and wildlife. Spatial heterogeneity is a common feature of landscapes in the Pacific Northwest, most notably in areas important to the production of salmonid fish species. This heterogeneity complicates attempts to design and implement policies to conserve the stocks of such species. To date, millions of dollars have been spent to improve habitat for salmonids, with mixed success. This research examines the spatial implications of habitat restoration activities for the benefit of endangered salmonid fish species. A theoretical model defining an economically efficient allocation of restoration practices is developed for a hypothetical stream with a range of hydrological and spatial characteristics. An integrated hydrological, biological and economic modeling approach is then developed, and an empirical analysis is applied to the upper Grande Ronde River basin in northeastern Oregon. Results of these analyses indicate that the heterogeneous nature of riparian conditions and stream morphology has a substantial effect on the efficacy of restoration activities. The minimum cost allocation of restoration activities for small temperature reductions is to apply restoration efforts to nearby upstream reaches, while cumulative effects become important as the magnitude of desired temperature reduction increases. However, as the magnitude of desired temperature reductions increases, temperature reduction per dollar of restoration efforts decreases rapidly. In terms of specific riparian restoration efforts, passive restoration is preferred to active restoration as the magnitude of desired temperature reductions decreases and / or as the time frame considered is increased. It is also less costly in general to implement restoration activities in tributaries if the objective is to maximize stream length where water temperatures decrease by a specific amount. When two targeting options are compared (a fish abundance goal vs. a temperature reduction goal), this study found that temperature targeting is inefficient in the sense that it is possible to produce a larger salmonid population with the same budget, and that the levels of temperature targets have significant impacts on fishery benefits. Title: A spatially explicit model for allocating conservation efforts : the Grand Ronde River basin, Oregon Author: Watanabe, Michio The spatial and dynamic pattern of landscape changes has a profound effect on the supply of environmental services, including the provision of habitat for fish and wildlife. Spatial heterogeneity is a common feature of landscapes in the Pacific Northwest, most notably in areas important to the production of salmonid fish species. This heterogeneity complicates attempts to design and implement policies to conserve the stocks of such species. To date, millions of dollars have been spent to improve habitat for salmonids, with mixed success. This research examines the spatial implications of habitat restoration activities for the benefit of endangered salmonid fish species. A theoretical model defining an economically efficient allocation of restoration practices is developed for a hypothetical stream with a range of hydrological and spatial characteristics. An integrated hydrological, biological and economic modeling approach is then developed, and an empirical analysis is applied to the upper Grande Ronde River basin in northeastern Oregon. Results of these analyses indicate that the heterogeneous nature of riparian conditions and stream morphology has a substantial effect on the efficacy of restoration activities. The minimum cost allocation of restoration activities for small temperature reductions is to apply restoration efforts to nearby upstream reaches, while cumulative effects become important as the magnitude of desired temperature reduction increases. However, as the magnitude of desired temperature reductions increases, temperature reduction per dollar of restoration efforts decreases rapidly. In terms of specific riparian restoration efforts, passive restoration is preferred to active restoration as the magnitude of desired temperature reductions decreases and / or as the time frame considered is increased. It is also less costly in general to implement restoration activities in tributaries if the objective is to maximize stream length where water temperatures decrease by a specific amount. When two targeting options are compared (a fish abundance goal vs. a temperature reduction goal), this study found that temperature targeting is inefficient in the sense that it is possible to produce a larger salmonid population with the same budget, and that the levels of temperature targets have significant impacts on fishery benefits. Close

• 13. [Article] Feeder dikes to the Columbia River flood basalts : underpinnings of a large igneous province

  Feeder dikes to the Columbia River Basalt Group (CRBG) large igneous province provide a rare opportunity to examine magma transport through the shallow crust during flood basalt eruptions. Over 70% of ...

  Citation × Citation Citation Abstract Copy Title: Feeder dikes to the Columbia River flood basalts : underpinnings of a large igneous province Author: Petcovic, Heather L. Feeder dikes to the Columbia River Basalt Group (CRBG) large igneous province provide a rare opportunity to examine magma transport through the shallow crust during flood basalt eruptions. Over 70% of the CRBG erupted from the Chief Joseph dike swarm, which is exposed across southeastern Washington, eastern Oregon, and western Idaho. The four manuscripts of this dissertation examine physical, thermal, and compositional characteristics of dikes from the southern Chief Joseph swarm. The majority of CRBG dikes are chilled against their wallrock, however, rare dikes have induced partial melting in their wallrock. Melt zones in tonalite wallrock adjacent to the Maxwell Lake dike are up to 4 in thick and contain up to 47 volume percent quenched silicic melt produced from dehydration-melting reactions involvir biotite, hornblende, quartz, orthoclase, and plagioclase. Melt zones record the thermal history of basalt flow and cooling in the Maxwell Lake dike, a feeder to Wapshilla Ridge flows (Grande Ronde Basalt). Results of one- and two-dimensional numerical modeling suggest that basalt flowed in the Maxwell Lake dike for 3-4 years, yielding maximum eruption rates of 3.4-4.6 km3/day for typical Wapshilla Ridge flows. The Maxwell Lake dike likely represents an upper crustal exposure of a long-lived point source in the CRBG. Chief Joseph dikes are concentrated into sub-swarms of 7-12 dikes per km2. Based on transects through four sub-swarms, dikes become more aligned, more frequent, thinner, and more closely spaced from northwest to southeast across the southern Chief Joseph swarm. Fewer than 2% of dikes, and less than 0.5% of cumulative dike length, had caused extensive melting in their wallrock. In the Cornucopia sub-swarm, numerical modeling of cross-cutting and compound dikes suggests that magmatic activity occurred intermittently over 2-4 years. Compositional data collected from -250 southern Chief Joseph dikes indicate that most are Grande Ronde Basalt, although isolated Imnaha and Dodge (Eckler Mountain Member, Wanapum Basalt) dikes also occur. Imnaha dikes are compositionally primitive, whereas Grande Ronde and Dodge dikes are more evolved. Subtle compositional differences between sub-swarms of Grande Ronde dikes suggest that each sub-swarm represents a discrete episode of Grande Ronde volcanism. Title: Feeder dikes to the Columbia River flood basalts : underpinnings of a large igneous province Author: Petcovic, Heather L. Feeder dikes to the Columbia River Basalt Group (CRBG) large igneous province provide a rare opportunity to examine magma transport through the shallow crust during flood basalt eruptions. Over 70% of the CRBG erupted from the Chief Joseph dike swarm, which is exposed across southeastern Washington, eastern Oregon, and western Idaho. The four manuscripts of this dissertation examine physical, thermal, and compositional characteristics of dikes from the southern Chief Joseph swarm. The majority of CRBG dikes are chilled against their wallrock, however, rare dikes have induced partial melting in their wallrock. Melt zones in tonalite wallrock adjacent to the Maxwell Lake dike are up to 4 in thick and contain up to 47 volume percent quenched silicic melt produced from dehydration-melting reactions involvir biotite, hornblende, quartz, orthoclase, and plagioclase. Melt zones record the thermal history of basalt flow and cooling in the Maxwell Lake dike, a feeder to Wapshilla Ridge flows (Grande Ronde Basalt). Results of one- and two-dimensional numerical modeling suggest that basalt flowed in the Maxwell Lake dike for 3-4 years, yielding maximum eruption rates of 3.4-4.6 km3/day for typical Wapshilla Ridge flows. The Maxwell Lake dike likely represents an upper crustal exposure of a long-lived point source in the CRBG. Chief Joseph dikes are concentrated into sub-swarms of 7-12 dikes per km2. Based on transects through four sub-swarms, dikes become more aligned, more frequent, thinner, and more closely spaced from northwest to southeast across the southern Chief Joseph swarm. Fewer than 2% of dikes, and less than 0.5% of cumulative dike length, had caused extensive melting in their wallrock. In the Cornucopia sub-swarm, numerical modeling of cross-cutting and compound dikes suggests that magmatic activity occurred intermittently over 2-4 years. Compositional data collected from -250 southern Chief Joseph dikes indicate that most are Grande Ronde Basalt, although isolated Imnaha and Dodge (Eckler Mountain Member, Wanapum Basalt) dikes also occur. Imnaha dikes are compositionally primitive, whereas Grande Ronde and Dodge dikes are more evolved. Subtle compositional differences between sub-swarms of Grande Ronde dikes suggest that each sub-swarm represents a discrete episode of Grande Ronde volcanism. Close

• 14. [Article] Evaluating the restoration potential of black cottonwood (Populus trichocarpa) from multiple scales of observation, Grande Ronde River Basin, Oregon, USA

  As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is ...

  Citation × Citation Citation Abstract Copy Title: Evaluating the restoration potential of black cottonwood (Populus trichocarpa) from multiple scales of observation, Grande Ronde River Basin, Oregon, USA Author: Hines, Cynthia A. As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is of critical conservation importance. Subsequently, the chronic degradation of aquatic and riparian ecosystems in the semi-arid and arid landscapes of the western U.S. is the focus of many recent research efforts. A study was undertaken to investigate historic and current black cottonwood populations in the Grande Ronde River Basin, northeastern Oregon, U.S.A., and evaluate restoration potential given present-day fluvial-geomorphic conditions and reproductive strategies. Black cottonwood (Populus trichocarpa), a dominant tree species in these semi-arid systems, has been severely impacted by intensive grazing, irrigation, and land conversion activities over the past one and a half centuries. With the explicit incorporation of space and time, a simple conceptual framework was developed to examine the ecological restoration potential of black cottonwood from ecological and evolutionary perspectives. Restoration potential is defined in this study in terms of availability of suitable habitat and source (i.e., seedpool) for future generations. Digital analyses of aerial photographs reveal changes in the extent, numbers, and total area of cottonwood communities and habitat since 1937. Restoration potential is evaluated using historic stream flow records, stream cross-section analysis to predict current stream discharge, and DNA RAPD procedures to assess the effects of changing stream geomorphology and disturbance regimes on cottonwood reproductive strategies. Optimal spatial and temporal conditions for potential restoration locations of black cottonwood have been identified relative to channel morphology and flood events (e.g., frequency and magnitude). This multiple scale mechnistic approach is used to evaluate the feasibility of restoration efforts toward the re-establishment of viable black cottonwood riparian plant communities in two sites in the upper Grande Ronde River Basin. Title: Evaluating the restoration potential of black cottonwood (Populus trichocarpa) from multiple scales of observation, Grande Ronde River Basin, Oregon, USA Author: Hines, Cynthia A. As a key factor contributing to slope stability, in-stream habitat for aquatic species (e.g., salmonids), nutrient cycling, and corridors for upland species, riparian vegetation and its maintenance is of critical conservation importance. Subsequently, the chronic degradation of aquatic and riparian ecosystems in the semi-arid and arid landscapes of the western U.S. is the focus of many recent research efforts. A study was undertaken to investigate historic and current black cottonwood populations in the Grande Ronde River Basin, northeastern Oregon, U.S.A., and evaluate restoration potential given present-day fluvial-geomorphic conditions and reproductive strategies. Black cottonwood (Populus trichocarpa), a dominant tree species in these semi-arid systems, has been severely impacted by intensive grazing, irrigation, and land conversion activities over the past one and a half centuries. With the explicit incorporation of space and time, a simple conceptual framework was developed to examine the ecological restoration potential of black cottonwood from ecological and evolutionary perspectives. Restoration potential is defined in this study in terms of availability of suitable habitat and source (i.e., seedpool) for future generations. Digital analyses of aerial photographs reveal changes in the extent, numbers, and total area of cottonwood communities and habitat since 1937. Restoration potential is evaluated using historic stream flow records, stream cross-section analysis to predict current stream discharge, and DNA RAPD procedures to assess the effects of changing stream geomorphology and disturbance regimes on cottonwood reproductive strategies. Optimal spatial and temporal conditions for potential restoration locations of black cottonwood have been identified relative to channel morphology and flood events (e.g., frequency and magnitude). This multiple scale mechnistic approach is used to evaluate the feasibility of restoration efforts toward the re-establishment of viable black cottonwood riparian plant communities in two sites in the upper Grande Ronde River Basin. Close

• 15. [Article] The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems

  Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, ...

  Citation × Citation Citation Abstract Copy Title: The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems Author: Case, Richard L. Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, these zones influence the integrity of the terrestrial as well as the entire aquatic-riverine ecosystem. Since Euro-American settlement in the West, the structure and condition of many riparian ecosystems has been significantly altered. To provide tools and an ecological perspective related to riparian restoration and management, and to document late 20th century headwater riparian structure and biomass in the Upper Grande Ronde Basin, this research project was undertaken. At Meadow Creek, the response of riparian hardwood species to the termination of livestock grazing was quantified. Regression equations were developed to predict shrub biomass. Permanently marked hardwood plants were measured annually to quantify parameters of growth (height, crown area, mainstem diameter, number of stems, biomass). Permanent belt transects on gravel bars were utilized to quantify rates of shrub establishment. Elk/deer-proof exclosures allowed the quantification of the browsing influence of wild ungulates. In 1991, initial shrub heights and densities reflected decades of grazing pressure. Mean heights of515 woody plants (14 species) was 47 cm and densities on gravel bars averaged 10.7 plants/100m². After two seasons without livestock grazing, mean crown volumes of willows (Salix spp.) increased 550% inside of wild ungulate exclosures and 195% outside, black cottonwood (Populus trichocarpa) 773% inside and 808% outside, and thin-leaf alder (Almis incana) 1046% inside and 198% outside, respectively. Willows were significantly impeded (p<0.Ol) mule deer and Rocky Mountain elk, alder samples were too small to statistically test, and cottonwood was not significantly impeded. However, impacts by deer and elk may be exaggerated due to high densities and the ungulate density-dynamics unique within the 77 km² Starkey Experimental Forest big-game enclosure surrounding the study site. Establishment rates are low at this time, i.e., only 10% of previously suppressed willows produced catkins. Although in transects densities increased by 5 new woody plants/lOOm² (50m of streambank). Other non-anthropogenic factors influencing the recovery of shrubs, included beaver which removed mainstems from 20% of willows, 11% of thin-leaf alder, and 4% of black cottonwood, and active insect defoliation which was noted on 16% of willows, 7% of thin-leaf alder, and 0% of black cottonwood. Crude protein levels measured in willow and alder leaves was relatively high (16.1 to 16.3%) helping to explain their palatability and use by wild and domestic herbivores. Few studies have quantified biomass, structure and composition of headwater riparian ecosystems. Data such as this are important given their dominant roles in ecosystem biodiversity, and aquatic function. To document relatively intact forested headwater ripanan conditions in the Upper Grande Ronde Basin, the biomass, structure and composition along six headwater reaches was quantified. Sampling was done using a nested belt transect/plot arrangement along 500 meter reaches. Total aboveground biomass (TAGB) ranged from 203 to 261 Mg/ha, with overstory conifers contributing 101 to 177 Mg/ha. Living understory components (saplings, seedlings, shrubs, and herbs) comprised 5 to 18 Mg/ha (2 to 9% of TAGB), while forest floor detrital accumulations comprised 65 to 101 Mg/ha (29 to 42% of TAGB). Average shade per day for July, 1993 ranged between 53% and 75%, reducing the unshaded solar energy potential of 2390 Mj/day to between 680 and 1280 Mj/day striking each m² of stream surface. This baseline reference information can serve in multi-disciplined research, as well as, be a basis for long term studies of natural systems responding to changing climate and different resource management scenarios. Title: The ecology of riparian ecosystems of Northeast Oregon : shrub recovery at Meadow Creek and the structure and biomass of headwater Upper Grande Ronde ecosystems Author: Case, Richard L. Riparian ecosystems play numerous and essential roles related to the quality and flow of water, and food/habitat for fish, and varieties of wildlife. Due to lateral and linear linkages throughout the landscape, these zones influence the integrity of the terrestrial as well as the entire aquatic-riverine ecosystem. Since Euro-American settlement in the West, the structure and condition of many riparian ecosystems has been significantly altered. To provide tools and an ecological perspective related to riparian restoration and management, and to document late 20th century headwater riparian structure and biomass in the Upper Grande Ronde Basin, this research project was undertaken. At Meadow Creek, the response of riparian hardwood species to the termination of livestock grazing was quantified. Regression equations were developed to predict shrub biomass. Permanently marked hardwood plants were measured annually to quantify parameters of growth (height, crown area, mainstem diameter, number of stems, biomass). Permanent belt transects on gravel bars were utilized to quantify rates of shrub establishment. Elk/deer-proof exclosures allowed the quantification of the browsing influence of wild ungulates. In 1991, initial shrub heights and densities reflected decades of grazing pressure. Mean heights of515 woody plants (14 species) was 47 cm and densities on gravel bars averaged 10.7 plants/100m². After two seasons without livestock grazing, mean crown volumes of willows (Salix spp.) increased 550% inside of wild ungulate exclosures and 195% outside, black cottonwood (Populus trichocarpa) 773% inside and 808% outside, and thin-leaf alder (Almis incana) 1046% inside and 198% outside, respectively. Willows were significantly impeded (p<0.Ol) mule deer and Rocky Mountain elk, alder samples were too small to statistically test, and cottonwood was not significantly impeded. However, impacts by deer and elk may be exaggerated due to high densities and the ungulate density-dynamics unique within the 77 km² Starkey Experimental Forest big-game enclosure surrounding the study site. Establishment rates are low at this time, i.e., only 10% of previously suppressed willows produced catkins. Although in transects densities increased by 5 new woody plants/lOOm² (50m of streambank). Other non-anthropogenic factors influencing the recovery of shrubs, included beaver which removed mainstems from 20% of willows, 11% of thin-leaf alder, and 4% of black cottonwood, and active insect defoliation which was noted on 16% of willows, 7% of thin-leaf alder, and 0% of black cottonwood. Crude protein levels measured in willow and alder leaves was relatively high (16.1 to 16.3%) helping to explain their palatability and use by wild and domestic herbivores. Few studies have quantified biomass, structure and composition of headwater riparian ecosystems. Data such as this are important given their dominant roles in ecosystem biodiversity, and aquatic function. To document relatively intact forested headwater ripanan conditions in the Upper Grande Ronde Basin, the biomass, structure and composition along six headwater reaches was quantified. Sampling was done using a nested belt transect/plot arrangement along 500 meter reaches. Total aboveground biomass (TAGB) ranged from 203 to 261 Mg/ha, with overstory conifers contributing 101 to 177 Mg/ha. Living understory components (saplings, seedlings, shrubs, and herbs) comprised 5 to 18 Mg/ha (2 to 9% of TAGB), while forest floor detrital accumulations comprised 65 to 101 Mg/ha (29 to 42% of TAGB). Average shade per day for July, 1993 ranged between 53% and 75%, reducing the unshaded solar energy potential of 2390 Mj/day to between 680 and 1280 Mj/day striking each m² of stream surface. This baseline reference information can serve in multi-disciplined research, as well as, be a basis for long term studies of natural systems responding to changing climate and different resource management scenarios. Close

• 16. [Article] Oregon State Game Commission bulletin; Vol.22 No.6 (November-December 1967)

  Contents: Senate Bill 8 Becomes Law - p.2; Can You Tell Me? [Receiving inquiries about fishing and hunting regulations] - p.3, 7-8; Steelhead Fishing Grande Ronde River - p.4-5; Cougar [Photos] - p.6; ...

  Citation × Citation Citation Abstract Copy Title: Oregon State Game Commission bulletin; Vol.22 No.6 (November-December 1967) Author: Oregon. State Game Commission Contents: Senate Bill 8 Becomes Law - p.2; Can You Tell Me? [Receiving inquiries about fishing and hunting regulations] - p.3, 7-8; Steelhead Fishing Grande Ronde River - p.4-5; Cougar [Photos] - p.6; The California Murre - p.8 Title: Oregon State Game Commission bulletin; Vol.22 No.6 (November-December 1967) Author: Oregon. State Game Commission Contents: Senate Bill 8 Becomes Law - p.2; Can You Tell Me? [Receiving inquiries about fishing and hunting regulations] - p.3, 7-8; Steelhead Fishing Grande Ronde River - p.4-5; Cougar [Photos] - p.6; The California Murre - p.8 Close

• 17. [Article] Results of trip to Snake River : 28 September -- 4 October 1957

  The mail boat trip was taken from Lewiston to Hells Canyon and return. Bathythermograph observations were made in deep holes at Buffalo Eddy, Nez Perce Dam site, and near Mountain Sheep Dam site. Thermograph ...

  Citation × Citation Citation Abstract Copy Title: Results of trip to Snake River : 28 September -- 4 October 1957 Author: Oregon State College. School of Science, Burt, Wayne V., U.S. Fish and Wildlife Service The mail boat trip was taken from Lewiston to Hells Canyon and return. Bathythermograph observations were made in deep holes at Buffalo Eddy, Nez Perce Dam site, and near Mountain Sheep Dam site. Thermograph sites on the Grande Ronde River were evaluated. A number of lakes, reservoirs, and dams were visited enroute to Lewiston. Title: Results of trip to Snake River : 28 September -- 4 October 1957 Author: Oregon State College. School of Science, Burt, Wayne V., U.S. Fish and Wildlife Service The mail boat trip was taken from Lewiston to Hells Canyon and return. Bathythermograph observations were made in deep holes at Buffalo Eddy, Nez Perce Dam site, and near Mountain Sheep Dam site. Thermograph sites on the Grande Ronde River were evaluated. A number of lakes, reservoirs, and dams were visited enroute to Lewiston. Close

• 18. [Article] Ecology of woody riparian vegetation in tributaries of the Upper Grande Ronde River basin, Oregon

  Two studies on Catherine Creek and Meadow Creek of the Upper Grande Ronde River basin, quantified several physical and biotic influences on woody riparian community composition and structure. The Catherine ...

  Citation × Citation Citation Abstract Copy Title: Ecology of woody riparian vegetation in tributaries of the Upper Grande Ronde River basin, Oregon Author: Lytjen, Danna J. Two studies on Catherine Creek and Meadow Creek of the Upper Grande Ronde River basin, quantified several physical and biotic influences on woody riparian community composition and structure. The Catherine Creek study examined the association of woody riparian species with elevational and geomorphic gradients. The Meadow Creek study examined the influence of mammal herbivory on composition and abundance of woody riparian species. At Catherine Creek, twenty nine plots were established at 50 m intervals of elevation from near the stream origin at 2207 m in the Wallowa Mountains to the foothills of the Grande Ronde Valley at 988 m. Woody plant community composition was associated with the dominant environmental variable, elevation. Distribution of dominant riparian species was strongly associated with fluvial surfaces. Black cottonwood (Populus balsamifera) was associated with gravel and cobble bars proximal to the stream channel, and along with ponderosa pine (Pinus ponderosa) was also associated with elevated boulder bars. Alders (A. incana and A. viridis) and willows (Salix bebbiana, S. boothii, S. exigua, S. lucida, S. melanopsis, S. prolixa, and S. sitchensis) were associated with annual floodplains. At Meadow Creek, grazing by cattle was ended in 1991 on the entire study reach and three deer and elk exclosures were built within the reach adjacent to the creek. Inside deer/elk exclosures from 1991 to 1995, mean heights of tagged cottonwoods, willows, and alders increased by 86% to 180%. Outside exclosures, mean heights of cottonwoods and alders increased 109% and 99% respectively, but willows showed little change in height. Both inside and outside of exclosures mean crown volume of cottonwoods increased over 1000% and mean crown volume of alders increased over 600%. Willow volume inside exclosures increased 376% in root sprouting (clonal) species and 528% in crown sprouting (non-clonal) species, while outside of exclosures volume increased 79% and 144% respectively. On both sides of exclosure fences, beaver herbivory had a significant effect on cottonwood height growth in 1994 and 1995, and on height and crown volume growth of willows in 1995. Over 50% of stem density increase on transects was attributable to expansion within two large clones of Salix melanopsis inside exclosures. Excluding these two clones, overall woody plant density increased by 72% from 3.7 plants per 100 m² of transect in 1991 to 6.3 plants per 100 m² of transect in 1995. Title: Ecology of woody riparian vegetation in tributaries of the Upper Grande Ronde River basin, Oregon Author: Lytjen, Danna J. Two studies on Catherine Creek and Meadow Creek of the Upper Grande Ronde River basin, quantified several physical and biotic influences on woody riparian community composition and structure. The Catherine Creek study examined the association of woody riparian species with elevational and geomorphic gradients. The Meadow Creek study examined the influence of mammal herbivory on composition and abundance of woody riparian species. At Catherine Creek, twenty nine plots were established at 50 m intervals of elevation from near the stream origin at 2207 m in the Wallowa Mountains to the foothills of the Grande Ronde Valley at 988 m. Woody plant community composition was associated with the dominant environmental variable, elevation. Distribution of dominant riparian species was strongly associated with fluvial surfaces. Black cottonwood (Populus balsamifera) was associated with gravel and cobble bars proximal to the stream channel, and along with ponderosa pine (Pinus ponderosa) was also associated with elevated boulder bars. Alders (A. incana and A. viridis) and willows (Salix bebbiana, S. boothii, S. exigua, S. lucida, S. melanopsis, S. prolixa, and S. sitchensis) were associated with annual floodplains. At Meadow Creek, grazing by cattle was ended in 1991 on the entire study reach and three deer and elk exclosures were built within the reach adjacent to the creek. Inside deer/elk exclosures from 1991 to 1995, mean heights of tagged cottonwoods, willows, and alders increased by 86% to 180%. Outside exclosures, mean heights of cottonwoods and alders increased 109% and 99% respectively, but willows showed little change in height. Both inside and outside of exclosures mean crown volume of cottonwoods increased over 1000% and mean crown volume of alders increased over 600%. Willow volume inside exclosures increased 376% in root sprouting (clonal) species and 528% in crown sprouting (non-clonal) species, while outside of exclosures volume increased 79% and 144% respectively. On both sides of exclosure fences, beaver herbivory had a significant effect on cottonwood height growth in 1994 and 1995, and on height and crown volume growth of willows in 1995. Over 50% of stem density increase on transects was attributable to expansion within two large clones of Salix melanopsis inside exclosures. Excluding these two clones, overall woody plant density increased by 72% from 3.7 plants per 100 m² of transect in 1991 to 6.3 plants per 100 m² of transect in 1995. Close

• 19. [Article] Revegetation with Carex nebrascensis and Carex utriculata following reconstruction in a NE Oregon meadow stream

  Riparian vegetation is an essential component for the maintenance and/or repair of channel stability and function. Sedges within low-gradient riparian systems provide the structure necessary for sediment ...

  Citation × Citation Citation Abstract Copy Title: Revegetation with Carex nebrascensis and Carex utriculata following reconstruction in a NE Oregon meadow stream Author: Quistberg, Sarah E. Riparian vegetation is an essential component for the maintenance and/or repair of channel stability and function. Sedges within low-gradient riparian systems provide the structure necessary for sediment trapping leading to channel narrowing through bank building processes. Planting success in riparian restoration projects has often failed due to inappropriate species selection, planting locations and/or methodologies. Stream restoration efforts utilizing channel reconstruction methods are increasing in number across the West thus emphasizing the need for knowledge on revegetation methods. Planting success in a recently constructed channel is essential because the lack of vegetation makes the channel highly susceptible to erosion. Sedges play an important role in the stability of low gradient, fine-textured stream channels. Two native sedges, Carex nebrascensis (Nebraska sedge) and Carex utriculata (beaked sedge) are often used in riparian restoration within the West because they have extensive root systems that can provide bank stability in fine-sediment channels. Survival and vegetative reproduction were evaluated on greenhouse grown plugs of these two sedge species following transplanting within a reconstructed NE Oregon meadow stream. Sedge plugs were planted on two fluvial surfaces along the stream: depositional (point bars) and erosional surfaces (straight) at or below bankfull level. A second study was performed to evaluate the effect of Cirsium arvense (Canada thistle) presence on sedge transplant survival and vegetative reproduction. This was performed only on erosional planting locations. Depths to groundwater and soil moisture were also recorded at each planting location. Survival at the end of the first growing season in the first study was the same for both species, but shoot numbers were greater for Carex nebrascensis (98 shoots/m²) compared with Carex utriculata (84 shoots/m²). No differences were observed between shoot numbers by species at the end of the second growing season. Greater shoot numbers also occurred on depositional planting locations (117 and 165 shoots/m²) compared to erosional planting locations (65 and 59 shoots/m²) at the end of the first and second growing seasons. Transplant loss due to scour from high flows was greater at erosional planting locations (48%) than at depositional planting surfaces (19%). Sedge transplant loss from scour during high flows was greater for Carex utriculata transplants (44%) than for Carex nebrascensis transplants (23%). Presence of Cirsium arvense was observed to be associated with a reduction in vegetative reproduction during the first growing season but not at the end of the second growing season. Carex nebrascensis produced more shoots than Carex utriculata regardless of thistle presence for both growing seasons probably due to depth to groundwater. Transplant loss due to scour from high flows was greater for Carex utriculata (55%) compared to Carex nebrascensis (28%). These results suggested that revegetation success will be increased if sedges are planted on depositional geomorphic surfaces within reconstructed meadow channels. Cirsium arvense may be controlled following sedge transplanting during the first growing season to increase vegetative growth. These results also suggested that Carex nebrascensis is an appropriate species for transplanting at sites with water tables deeper than 30 cm. Title: Revegetation with Carex nebrascensis and Carex utriculata following reconstruction in a NE Oregon meadow stream Author: Quistberg, Sarah E. Riparian vegetation is an essential component for the maintenance and/or repair of channel stability and function. Sedges within low-gradient riparian systems provide the structure necessary for sediment trapping leading to channel narrowing through bank building processes. Planting success in riparian restoration projects has often failed due to inappropriate species selection, planting locations and/or methodologies. Stream restoration efforts utilizing channel reconstruction methods are increasing in number across the West thus emphasizing the need for knowledge on revegetation methods. Planting success in a recently constructed channel is essential because the lack of vegetation makes the channel highly susceptible to erosion. Sedges play an important role in the stability of low gradient, fine-textured stream channels. Two native sedges, Carex nebrascensis (Nebraska sedge) and Carex utriculata (beaked sedge) are often used in riparian restoration within the West because they have extensive root systems that can provide bank stability in fine-sediment channels. Survival and vegetative reproduction were evaluated on greenhouse grown plugs of these two sedge species following transplanting within a reconstructed NE Oregon meadow stream. Sedge plugs were planted on two fluvial surfaces along the stream: depositional (point bars) and erosional surfaces (straight) at or below bankfull level. A second study was performed to evaluate the effect of Cirsium arvense (Canada thistle) presence on sedge transplant survival and vegetative reproduction. This was performed only on erosional planting locations. Depths to groundwater and soil moisture were also recorded at each planting location. Survival at the end of the first growing season in the first study was the same for both species, but shoot numbers were greater for Carex nebrascensis (98 shoots/m²) compared with Carex utriculata (84 shoots/m²). No differences were observed between shoot numbers by species at the end of the second growing season. Greater shoot numbers also occurred on depositional planting locations (117 and 165 shoots/m²) compared to erosional planting locations (65 and 59 shoots/m²) at the end of the first and second growing seasons. Transplant loss due to scour from high flows was greater at erosional planting locations (48%) than at depositional planting surfaces (19%). Sedge transplant loss from scour during high flows was greater for Carex utriculata transplants (44%) than for Carex nebrascensis transplants (23%). Presence of Cirsium arvense was observed to be associated with a reduction in vegetative reproduction during the first growing season but not at the end of the second growing season. Carex nebrascensis produced more shoots than Carex utriculata regardless of thistle presence for both growing seasons probably due to depth to groundwater. Transplant loss due to scour from high flows was greater for Carex utriculata (55%) compared to Carex nebrascensis (28%). These results suggested that revegetation success will be increased if sedges are planted on depositional geomorphic surfaces within reconstructed meadow channels. Cirsium arvense may be controlled following sedge transplanting during the first growing season to increase vegetative growth. These results also suggested that Carex nebrascensis is an appropriate species for transplanting at sites with water tables deeper than 30 cm. Close

• 20. [Article] The geology of the Nicolai Mountain-Gnat Creek area, Clatsop County, northwestern Oregon

  Twelve rock units, from upper Eocene to middle Miocene are exposed in the Nicolai Mountain-Gnat Creek area. They are, from oldest to youngest: Pittsburg Bluff Formation; Oswald West mudstone; Big Creek ...

  Citation × Citation Citation Abstract Copy Title: The geology of the Nicolai Mountain-Gnat Creek area, Clatsop County, northwestern Oregon Author: Murphy, Thomas M. Twelve rock units, from upper Eocene to middle Miocene are exposed in the Nicolai Mountain-Gnat Creek area. They are, from oldest to youngest: Pittsburg Bluff Formation; Oswald West mudstone; Big Creek sandstone, upper Silver Point mudstone, and Pipeline mudstone members of the Astoria Formation; Depoe Bay Basalt; Grande Ronde Basalt; Cape Foulweather Basalt; and sandstone correlative to the Vantage Member of the Ellensburg Formation; Frenchman Springs Member of the Wanapum Basalt; Clifton, Formation (defined by author); and Pomona Member of the Saddle Mountains Basalt. Upper Eocene Pittsburg Bluff Formation is a fine-grained sandstone and laminated siltstone deposited in an inner to middle continental shelf environment. Concordant onlapping by the upper Oligocene, middle shelf to upper slope glauconitic Oswald West mudstone, establishes a tie between the northeastern and northwestern Oregon Coast Range stratigraphies. The lower to middle Miocene Astoria Formation represents another marine onlap sequence, beginning with the fine-grained cross-bedded inner shelf Big Creek sandstone member. The overlying laminted upper Silver Point and Pipeline mudstone members were deposited in a deepening middle shelf to upper slope environment. The middle Miocene tholeiitic basalts extruded from two sources. Grande Ronde, Frenchman Springs, and Pomona basalts of the Columbia River Group erupted from fissures east of the Cascades and flowed down an ancestral Columbia River valley entering the sea in the study area. Simultaneously, petrologically similar but less voluminous Depoe Bay and Cape Foulweather are correlative to the low MgO Grande Ronde and Frenchman Springs in the study area. Abundant dikes and sills and the bathyal mudstone interbeds suggest that the coastal pillow basalts extruded locally onto the sea floor. Subaerial plateau-derived flows are associated with cross-bedded, fluvial to shallow marine arkosic sandstone interbeds. Some of these subaerial lavas flowed into the sea, forming "lava deltas" of foreset pillow palagonite and possibly "invasive" sills. The basalt stratigraphy allows a nearly flow by flow correlation of Grande Ronde and Frenchman Springs units from the Clackamas River area (Western Cascades) into this study area. The presence of Pomona Member in this area is the first substantiated recognition of this petrologically and chemically distinctive subaerial flow in northwestern Oregon. The 200-meter thick Clifton formation (previously called the Pliocene (?) sandstone at Clifton) is now dated by diatom assemblages and stratigraphic position as middle Miocene in age. Three lithofacies are recognized. Facies 1, at the base and top of the unit, is an arkosic, fine- to coarse- grained sandstone with cross-bedding, vertical Rosselia burrows, lignitic coal beds, and rare molluscan shells. It represents a river mouth and shallow marine offshore bar deposit. Facies 2, in the middle of the formation, consitst of well-laminated diatom-bearing carbonaceous and micaceous shelf/slope siltstones with thin fine-grained turbidite sandstones. Facies consists of channelized siltstone breccias, chaotic debris flows, thick amalgamated arkosic grain flows, structureless sandstones, and minor volcanic pebble conglomerates. These lithologies suggest a canyon head and slump deposit formed as a submarine channel cut into the shelf/slope siltstones of Facies 2. Sandstone petrography and grain size analyses indicate that the detritus of the Clifton and other sandstones in the area was derived from acid igneous, metamorphic, and intermediate volcanic provenances similar to those drained by the Columbia River today. Despite high measured permeabilities, breaching limits the reservoir potential of the sandstone. Mudstone units are immature to mature hydrocarbon source rocks. A potential for gas exists in the Cowlitz or its equivalent in the subsurface and in the Clifton channel sandstones projected into the offshore area. Title: The geology of the Nicolai Mountain-Gnat Creek area, Clatsop County, northwestern Oregon Author: Murphy, Thomas M. Twelve rock units, from upper Eocene to middle Miocene are exposed in the Nicolai Mountain-Gnat Creek area. They are, from oldest to youngest: Pittsburg Bluff Formation; Oswald West mudstone; Big Creek sandstone, upper Silver Point mudstone, and Pipeline mudstone members of the Astoria Formation; Depoe Bay Basalt; Grande Ronde Basalt; Cape Foulweather Basalt; and sandstone correlative to the Vantage Member of the Ellensburg Formation; Frenchman Springs Member of the Wanapum Basalt; Clifton, Formation (defined by author); and Pomona Member of the Saddle Mountains Basalt. Upper Eocene Pittsburg Bluff Formation is a fine-grained sandstone and laminated siltstone deposited in an inner to middle continental shelf environment. Concordant onlapping by the upper Oligocene, middle shelf to upper slope glauconitic Oswald West mudstone, establishes a tie between the northeastern and northwestern Oregon Coast Range stratigraphies. The lower to middle Miocene Astoria Formation represents another marine onlap sequence, beginning with the fine-grained cross-bedded inner shelf Big Creek sandstone member. The overlying laminted upper Silver Point and Pipeline mudstone members were deposited in a deepening middle shelf to upper slope environment. The middle Miocene tholeiitic basalts extruded from two sources. Grande Ronde, Frenchman Springs, and Pomona basalts of the Columbia River Group erupted from fissures east of the Cascades and flowed down an ancestral Columbia River valley entering the sea in the study area. Simultaneously, petrologically similar but less voluminous Depoe Bay and Cape Foulweather are correlative to the low MgO Grande Ronde and Frenchman Springs in the study area. Abundant dikes and sills and the bathyal mudstone interbeds suggest that the coastal pillow basalts extruded locally onto the sea floor. Subaerial plateau-derived flows are associated with cross-bedded, fluvial to shallow marine arkosic sandstone interbeds. Some of these subaerial lavas flowed into the sea, forming "lava deltas" of foreset pillow palagonite and possibly "invasive" sills. The basalt stratigraphy allows a nearly flow by flow correlation of Grande Ronde and Frenchman Springs units from the Clackamas River area (Western Cascades) into this study area. The presence of Pomona Member in this area is the first substantiated recognition of this petrologically and chemically distinctive subaerial flow in northwestern Oregon. The 200-meter thick Clifton formation (previously called the Pliocene (?) sandstone at Clifton) is now dated by diatom assemblages and stratigraphic position as middle Miocene in age. Three lithofacies are recognized. Facies 1, at the base and top of the unit, is an arkosic, fine- to coarse- grained sandstone with cross-bedding, vertical Rosselia burrows, lignitic coal beds, and rare molluscan shells. It represents a river mouth and shallow marine offshore bar deposit. Facies 2, in the middle of the formation, consitst of well-laminated diatom-bearing carbonaceous and micaceous shelf/slope siltstones with thin fine-grained turbidite sandstones. Facies consists of channelized siltstone breccias, chaotic debris flows, thick amalgamated arkosic grain flows, structureless sandstones, and minor volcanic pebble conglomerates. These lithologies suggest a canyon head and slump deposit formed as a submarine channel cut into the shelf/slope siltstones of Facies 2. Sandstone petrography and grain size analyses indicate that the detritus of the Clifton and other sandstones in the area was derived from acid igneous, metamorphic, and intermediate volcanic provenances similar to those drained by the Columbia River today. Despite high measured permeabilities, breaching limits the reservoir potential of the sandstone. Mudstone units are immature to mature hydrocarbon source rocks. A potential for gas exists in the Cowlitz or its equivalent in the subsurface and in the Clifton channel sandstones projected into the offshore area. Close

• 21. [Article] Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability

  Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution ...

  Citation × Citation Citation Abstract Copy Title: Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability Author: Yancey, Jennifer M. Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack of measurable criteria for the assessment of a riparian systems modified by human imposed infrastructures. The woody vegetation community offered a quantifiable indicator of the underlying mosaic of environmental, physical, and hydrological attributes, while allowing the investigation of the concept of riparian potential versus riparian capability. The examination of riparian condition was measured through the determination of species-environmental relationships along three mountainous channels in northeast Oregon. The physical and environmental attributes of channel morphology, hydrology, understory community composition, surface particle characteristics, and microclimate variables were quantified and analyzed in relation to the woody vegetation composition and distribution across the three separate streams and within flood-frequency elevation zones. The second component of the study evaluated and described methods for quantifying the concept of riparian capability, based on the measured species-environmental relationships and channel morphology. The evaluation of condition was measured against the reference baseline of Rosgen hierarchical classification and regional hydraulic geometry curves. Multivariate analyses indicated that vegetation transects grouped by stream and vegetation belt transects weakly grouped by flood zone, based on the species composition quantified within the vegetation transects and flood zones. Secondly, channel geometry, canopy cover, air temperature, channel particle size, understory composition attributes, and flood zone distance were found to be overall gradients, which described the variation in species composition across the three streams in northeast Oregon. Direct individual species-environmental relationship conclusions were weak due to the close clustering of species and multiple physical and environmental gradients. Riparian condition at the Grande Ronde River and North Fork Catherine Creek was determined to be functioning at riparian capability. Channel geometry measurements at the two stream reaches aligned with Rosgen stream type criteria and regional hydrologic curves, while species composition represented characteristics of potential natural communities. Meadow Creek was concluded to have departed from the highest attainable condition, thus riparian condition was less than capability. The results suggested that woody riparian vegetation response was a function the physical sttributes: channel morphological widths, bankfull, floodprone, 25-year flood width, valley width, channel sinuosity, and channel slope. Environmental attributes, floodplain canopy cover, air temperature, and understory composition, were further factors that influenced the woody riparian vegetation community variation. The results also suggested species richness and diversity were associated with specific physical and environmental attributes. Finally, the results provided the determination of riparian capability along montane streams in northeast Oregon and criteria acceptable for the determination of riparian capability. These criteria included the physical channel measurements assessed against Rosgen hierarchiecal classification and regional channel geometry curves; and woody vegetation presence and distribution assessed against potential natural community plant associations. Further research should be done across a variety of riparian systems to determine both indicator species and reference values for the physical and environmental attributes that could be utilized for the assessment of riparian capability. Title: Woody riparian species patterns along northeast Oregon mountainous streams and the relationship to riparian capability Author: Yancey, Jennifer M. Woody riparian vegetation is an essential component of riparian ecosystems, responsible in part for the maintenance of functional ecological processes. The plant community composition and distribution provide an indication of the underlying mosaic of environmental attributes and processes. Restoration and management of riparian communities have been hindered by the lack of measurable criteria for the assessment of a riparian systems modified by human imposed infrastructures. The woody vegetation community offered a quantifiable indicator of the underlying mosaic of environmental, physical, and hydrological attributes, while allowing the investigation of the concept of riparian potential versus riparian capability. The examination of riparian condition was measured through the determination of species-environmental relationships along three mountainous channels in northeast Oregon. The physical and environmental attributes of channel morphology, hydrology, understory community composition, surface particle characteristics, and microclimate variables were quantified and analyzed in relation to the woody vegetation composition and distribution across the three separate streams and within flood-frequency elevation zones. The second component of the study evaluated and described methods for quantifying the concept of riparian capability, based on the measured species-environmental relationships and channel morphology. The evaluation of condition was measured against the reference baseline of Rosgen hierarchical classification and regional hydraulic geometry curves. Multivariate analyses indicated that vegetation transects grouped by stream and vegetation belt transects weakly grouped by flood zone, based on the species composition quantified within the vegetation transects and flood zones. Secondly, channel geometry, canopy cover, air temperature, channel particle size, understory composition attributes, and flood zone distance were found to be overall gradients, which described the variation in species composition across the three streams in northeast Oregon. Direct individual species-environmental relationship conclusions were weak due to the close clustering of species and multiple physical and environmental gradients. Riparian condition at the Grande Ronde River and North Fork Catherine Creek was determined to be functioning at riparian capability. Channel geometry measurements at the two stream reaches aligned with Rosgen stream type criteria and regional hydrologic curves, while species composition represented characteristics of potential natural communities. Meadow Creek was concluded to have departed from the highest attainable condition, thus riparian condition was less than capability. The results suggested that woody riparian vegetation response was a function the physical sttributes: channel morphological widths, bankfull, floodprone, 25-year flood width, valley width, channel sinuosity, and channel slope. Environmental attributes, floodplain canopy cover, air temperature, and understory composition, were further factors that influenced the woody riparian vegetation community variation. The results also suggested species richness and diversity were associated with specific physical and environmental attributes. Finally, the results provided the determination of riparian capability along montane streams in northeast Oregon and criteria acceptable for the determination of riparian capability. These criteria included the physical channel measurements assessed against Rosgen hierarchiecal classification and regional channel geometry curves; and woody vegetation presence and distribution assessed against potential natural community plant associations. Further research should be done across a variety of riparian systems to determine both indicator species and reference values for the physical and environmental attributes that could be utilized for the assessment of riparian capability. Close

• 22. [Article] Detailed Morphology and Structure of an Active Submarine Arc Caldera: Brothers Volcano, Kermadec Arc

  This is a scanned version of a published article. The original can be found at: http://econgeol.geoscienceworld.org/. To the best of our knowledge, one or more authors of this paper were federal employees ...

  Citation × Citation Citation Abstract Copy Title: Detailed Morphology and Structure of an Active Submarine Arc Caldera: Brothers Volcano, Kermadec Arc Author: Tontini, F. Caratobi, Davy, B., Merle, S. G., de Ronde, C. E. J., Embley, R. W. This is a scanned version of a published article. The original can be found at: http://econgeol.geoscienceworld.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Title: Detailed Morphology and Structure of an Active Submarine Arc Caldera: Brothers Volcano, Kermadec Arc Author: Tontini, F. Caratobi, Davy, B., Merle, S. G., de Ronde, C. E. J., Embley, R. W. This is a scanned version of a published article. The original can be found at: http://econgeol.geoscienceworld.org/. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. Close

• 23. [Article] Multiscale habitat electivity and movement patterns by adult spring chinook salmon in seven river basins of northeast Oregon

  I examined habitat electivity and movement patterns of adult spring chinook salmon at microhabitat and channel unit spatial scales, and seasonal to annual temporal scales in seven streams in the Grande ...

  Citation × Citation Citation Abstract Copy Title: Multiscale habitat electivity and movement patterns by adult spring chinook salmon in seven river basins of northeast Oregon Author: Price, David M. I examined habitat electivity and movement patterns of adult spring chinook salmon at microhabitat and channel unit spatial scales, and seasonal to annual temporal scales in seven streams in the Grande Ronde, John Day, and Imnaha basins. The objective was to compare habitat use and availability among streams, channel units, and microhabitats, and to assess chinook salmon fidelity to those habitats using radio-telemetry. The analyses showed that habitat quality and availability in the seven study streams varied. Each stream posed different physical constraints on adult chinook salmon habitat; this was reflected by the differential use of habitat by salmon among streams. Salmon elected pools almost exclusively in the John Day Basin, whereas pools and riffles were elected in near equal proportion in the Grande Ronde and Inmaha basins. Within streams, use was similar between years. Almost all salmon were observed in association with cover, but the type of cover largely reflected availablity. Chinook salmon elected the deepest depths within channel units (microhabitat scale), but not necessarily the deepest channel units among streams (channel unit scale). Chinook salmon did not elect cooler stream temperatures within channel units in any study stream, except the Middle Fork John Day River. Radio-tagged chinook showed a high fidelity to habitats, except when stream temperatures approached lethal limits. Due to stream specific differences in habitat availability and use, multiscale habitat assessments for individual streams are recommended to increase the success of watershed restoration activities. Title: Multiscale habitat electivity and movement patterns by adult spring chinook salmon in seven river basins of northeast Oregon Author: Price, David M. I examined habitat electivity and movement patterns of adult spring chinook salmon at microhabitat and channel unit spatial scales, and seasonal to annual temporal scales in seven streams in the Grande Ronde, John Day, and Imnaha basins. The objective was to compare habitat use and availability among streams, channel units, and microhabitats, and to assess chinook salmon fidelity to those habitats using radio-telemetry. The analyses showed that habitat quality and availability in the seven study streams varied. Each stream posed different physical constraints on adult chinook salmon habitat; this was reflected by the differential use of habitat by salmon among streams. Salmon elected pools almost exclusively in the John Day Basin, whereas pools and riffles were elected in near equal proportion in the Grande Ronde and Inmaha basins. Within streams, use was similar between years. Almost all salmon were observed in association with cover, but the type of cover largely reflected availablity. Chinook salmon elected the deepest depths within channel units (microhabitat scale), but not necessarily the deepest channel units among streams (channel unit scale). Chinook salmon did not elect cooler stream temperatures within channel units in any study stream, except the Middle Fork John Day River. Radio-tagged chinook showed a high fidelity to habitats, except when stream temperatures approached lethal limits. Due to stream specific differences in habitat availability and use, multiscale habitat assessments for individual streams are recommended to increase the success of watershed restoration activities. Close

• 24. [Article] The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Society ...

  Citation × Citation Citation Abstract Copy Title: The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand Author: Ditchburn, R. G., Walker, S. L., et al., Merle, S. G., de Ronde, C. E. J. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Society of Economic Geologists and can be found at: http://economicgeology.org/. Title: The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand Author: Ditchburn, R. G., Walker, S. L., et al., Merle, S. G., de Ronde, C. E. J. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by the Society of Economic Geologists and can be found at: http://economicgeology.org/. Close

• 25. [Article] Maintaining fertility of Grande Ronde Valley soils

  Published March 1933. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog...

  Citation × Citation Citation Abstract Copy Title: Maintaining fertility of Grande Ronde Valley soils Author: Richards, D. E. (Dale Everette), 1892-, Oregon State Agricultural College. Agricultural Experiment Station, Powers, W. L. (Wilbur Louis), b. 1887 Published March 1933. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Maintaining fertility of Grande Ronde Valley soils Author: Richards, D. E. (Dale Everette), 1892-, Oregon State Agricultural College. Agricultural Experiment Station, Powers, W. L. (Wilbur Louis), b. 1887 Published March 1933. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 26. [Article] Reconnaissance report on the Wallowa Mountain and eastern Blue Mountain areas : including the drainages of Birch Creek, Burnt River, Powder River, Pine Creek, Imnaha River, Grande Ronde River and Asotin Creek

  Citation × Citation Citation Abstract Copy Title: Reconnaissance report on the Wallowa Mountain and eastern Blue Mountain areas : including the drainages of Birch Creek, Burnt River, Powder River, Pine Creek, Imnaha River, Grande Ronde River and Asotin Creek Author: MacDuffee, K. M. Title: Reconnaissance report on the Wallowa Mountain and eastern Blue Mountain areas : including the drainages of Birch Creek, Burnt River, Powder River, Pine Creek, Imnaha River, Grande Ronde River and Asotin Creek Author: MacDuffee, K. M. Close

• 27. [Article] Winter grain mite: a fall and winter pest of cereals and grasses in Oregon

  Published March 2009. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog

  Citation × Citation Citation Abstract Copy Title: Winter grain mite: a fall and winter pest of cereals and grasses in Oregon Author: Fisher, G., Tuck, Brain V., Bohle, Mylen G., Dreves, A., Oregon State University. Extension Service Published March 2009. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Title: Winter grain mite: a fall and winter pest of cereals and grasses in Oregon Author: Fisher, G., Tuck, Brain V., Bohle, Mylen G., Dreves, A., Oregon State University. Extension Service Published March 2009. Reviewed July 2013. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog Close

• 28. [Article] Geology of the Green Mountain-Young's River area, Clatsop County, northwest Oregon

  The upper Eocene to lower Oligocene Oswald West mudstone is the oldest formation (informal) in the Green Mountain-Young's River area. This 1,663 meter thick hemipelagic sequence was deposited in a low-energy ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Green Mountain-Young's River area, Clatsop County, northwest Oregon Author: Peterson, Carolyn Pugh The upper Eocene to lower Oligocene Oswald West mudstone is the oldest formation (informal) in the Green Mountain-Young's River area. This 1,663 meter thick hemipelagic sequence was deposited in a low-energy lower to upper slope environment in the Coast Range forearc basin. The formation ranges from the late Narizian to the early Zemorrian(?) in age and consists of thick-bedded bioturbated foraminiferal claystone and tuffaceous siltstone. Rare glauconitic sandstone beds also occur. In the eastern part of the study area, the upper part of the Oswald West mudstone is interbedded with the upper Refugian Klaskanine siltstone tongue. This informal unit consists of thick bioturbated sandy siltstone and silty sandstone that is a lateral deep-marine correlative of the deltaic to shallow-marine Pittsburg Bluff Formation in the northeastern Coast Range. Discontinuous underthrusting of the Juan de Fuca oceanic plate at the base of the continental slope of the North American plate caused extensive uplift and subsidence along the Oregon continental margin throughout the Cenozoic (Snavely et al., 1980). Initiation of Oregon Coast Range uplift and accompanying erosion in the early Miocene, coupled with a global low stand of sea level (Vail and Mitchum, 1979), stripped most of the Oligocene (Zemorrian) Oswald West strata and in places much of the uppermost Eocene (upper Refugian) Oswald West strata in the field area, creating an unconformity. Deformation accompanying uplift included a system of east-west-trending, oblique-slip faults. The Pillarian-to-Newportian Astoria Formation unconformably overlies the Oswald West mudstone and reflects deposition offshore from an open, storm-dominated coast during an early-to-middle Miocene transgression. Deposition of the Big Creek sandstone and Silver Point mudstone members of the Astoria Formation was controlled in part by submarine paleotopography that developed as a result of early Miocene deformation of the Oswald West strata. The up to 200 meter thick Big Creek member varies from storm-deposited laminated sandstone to bioturbated mollusk-bearing silty sandstone that accumulated during fair weather conditions on the inner to middle shelf. Overlying and perhaps in part laterally equivalent to the Big Creek member is the up to 200 meter thick, deeper marine Silver Point member which consists of two lithologies: 1) interbedded, micaceous, turbidite sandstones and laminated mudstone; and 2) laminated bathyal mudstone that intertongues with and caps the turbidite sequences. The turbidite lithology is composed of two facies: 1) an underlying sand-rich facies, transitional between the shallow-marine Big Creek member and bathyal Silver Point strata, that was deposited on the outer shelf by storm-induced turbidity currents; and 2) an overlying sand-poor facies that was deposited at bathyal depths. The turbidite facies channelized, and at some places removed the underlying Big Creek member and were deposited directly over Oswald West mudstone. The Astoria depositional sequence ranges, from inner to outer neritic to bathyal facies and reflects continued deepening and anoxic depositional conditions of the Astoria basin through the middle Miocene. Big Creek and Silver Point sandstone petrology reflects volcanic sources from an ancestral western Cascades volcanic arc and metamorphic and granitic basement rocks farther east via an ancestral Columbia River drainage system. Diagenetic effects include: (a) formation of local calcite concretionary cements; and (b) formation of pore-filling smectite from alteration of volcanic rock fragments. At least six middle Miocene Columbia River Basalt intrusive episodes affected the Green Mountain-Young's River area soon after deposition of the Astoria Formation. These basalt sills and dikes include normally polarized and reversely polarized low Mg0 high TiO₂, low Mg0 low TiO₂, and high Mg0 Grande Ronde basalt chemical subtypes and two porphyritic Frenchman Springs Member basalts (Ginkgo and Kelly Hollow(?) petrologic types). These basalt intrusions are virtually indistinguishable, based on chemistry, from subaerial flows of the plateau-derived Columbia River Basalt Group subtypes at nearby Nicolai Mountain and Porter Ridge. This correlation supports the Beeson et al. (1979) hypothesis that the intrusions are not of local origin but formed by the invasion of the flows into the Miocene shoreline sediments to form "invasive" sills and dikes. Many dikes were emplaced along northeast- and northwest-trending faults, and some (i.e., Ginkgo) cut older sills (Grande Ronde). A laterally extensive Frenchman Springs sill occurs under an older widespread Grande Ronde sill. From this older over younger intrusive relationship, a mechanism of "invasion" of sediment from overlying lava flows is difficult to envision. A pulse of rapid subduction starting in the middle Miocene (Snavely et al., 1980) was accompanied by renewed uplift, intensive block faulting, and continued development of the earlier formed Coast Range uplift. Left-oblique northeast-trending faults and conjugate northwest-trending right-oblique faults offset Grande Ronde and Frenchman Springs dikes and sills. This conjugate fault pattern may reflect oblique east-west convergence between the North American and Juan de Fuca plates. The Silver Point mudstones and Oswald West mudstones have high total organic carbon contents, up to 5.5%, but are thermally immature and may act only as a source for biogenic gas(?) in the subsurface. Suitable reservoir rocks, such as the gas-producing upper Eocene Cowlitz Formation C & W sandstone, may pinch out before reaching the Green Mountain-Young's River area and are yet to be penetrated by exploration drilling. Post-middle Miocene fault traps abound in the area, although these faults might also breach subsurface natural gas reservoirs in the Green Mountain-Young's River area. Title: Geology of the Green Mountain-Young's River area, Clatsop County, northwest Oregon Author: Peterson, Carolyn Pugh The upper Eocene to lower Oligocene Oswald West mudstone is the oldest formation (informal) in the Green Mountain-Young's River area. This 1,663 meter thick hemipelagic sequence was deposited in a low-energy lower to upper slope environment in the Coast Range forearc basin. The formation ranges from the late Narizian to the early Zemorrian(?) in age and consists of thick-bedded bioturbated foraminiferal claystone and tuffaceous siltstone. Rare glauconitic sandstone beds also occur. In the eastern part of the study area, the upper part of the Oswald West mudstone is interbedded with the upper Refugian Klaskanine siltstone tongue. This informal unit consists of thick bioturbated sandy siltstone and silty sandstone that is a lateral deep-marine correlative of the deltaic to shallow-marine Pittsburg Bluff Formation in the northeastern Coast Range. Discontinuous underthrusting of the Juan de Fuca oceanic plate at the base of the continental slope of the North American plate caused extensive uplift and subsidence along the Oregon continental margin throughout the Cenozoic (Snavely et al., 1980). Initiation of Oregon Coast Range uplift and accompanying erosion in the early Miocene, coupled with a global low stand of sea level (Vail and Mitchum, 1979), stripped most of the Oligocene (Zemorrian) Oswald West strata and in places much of the uppermost Eocene (upper Refugian) Oswald West strata in the field area, creating an unconformity. Deformation accompanying uplift included a system of east-west-trending, oblique-slip faults. The Pillarian-to-Newportian Astoria Formation unconformably overlies the Oswald West mudstone and reflects deposition offshore from an open, storm-dominated coast during an early-to-middle Miocene transgression. Deposition of the Big Creek sandstone and Silver Point mudstone members of the Astoria Formation was controlled in part by submarine paleotopography that developed as a result of early Miocene deformation of the Oswald West strata. The up to 200 meter thick Big Creek member varies from storm-deposited laminated sandstone to bioturbated mollusk-bearing silty sandstone that accumulated during fair weather conditions on the inner to middle shelf. Overlying and perhaps in part laterally equivalent to the Big Creek member is the up to 200 meter thick, deeper marine Silver Point member which consists of two lithologies: 1) interbedded, micaceous, turbidite sandstones and laminated mudstone; and 2) laminated bathyal mudstone that intertongues with and caps the turbidite sequences. The turbidite lithology is composed of two facies: 1) an underlying sand-rich facies, transitional between the shallow-marine Big Creek member and bathyal Silver Point strata, that was deposited on the outer shelf by storm-induced turbidity currents; and 2) an overlying sand-poor facies that was deposited at bathyal depths. The turbidite facies channelized, and at some places removed the underlying Big Creek member and were deposited directly over Oswald West mudstone. The Astoria depositional sequence ranges, from inner to outer neritic to bathyal facies and reflects continued deepening and anoxic depositional conditions of the Astoria basin through the middle Miocene. Big Creek and Silver Point sandstone petrology reflects volcanic sources from an ancestral western Cascades volcanic arc and metamorphic and granitic basement rocks farther east via an ancestral Columbia River drainage system. Diagenetic effects include: (a) formation of local calcite concretionary cements; and (b) formation of pore-filling smectite from alteration of volcanic rock fragments. At least six middle Miocene Columbia River Basalt intrusive episodes affected the Green Mountain-Young's River area soon after deposition of the Astoria Formation. These basalt sills and dikes include normally polarized and reversely polarized low Mg0 high TiO₂, low Mg0 low TiO₂, and high Mg0 Grande Ronde basalt chemical subtypes and two porphyritic Frenchman Springs Member basalts (Ginkgo and Kelly Hollow(?) petrologic types). These basalt intrusions are virtually indistinguishable, based on chemistry, from subaerial flows of the plateau-derived Columbia River Basalt Group subtypes at nearby Nicolai Mountain and Porter Ridge. This correlation supports the Beeson et al. (1979) hypothesis that the intrusions are not of local origin but formed by the invasion of the flows into the Miocene shoreline sediments to form "invasive" sills and dikes. Many dikes were emplaced along northeast- and northwest-trending faults, and some (i.e., Ginkgo) cut older sills (Grande Ronde). A laterally extensive Frenchman Springs sill occurs under an older widespread Grande Ronde sill. From this older over younger intrusive relationship, a mechanism of "invasion" of sediment from overlying lava flows is difficult to envision. A pulse of rapid subduction starting in the middle Miocene (Snavely et al., 1980) was accompanied by renewed uplift, intensive block faulting, and continued development of the earlier formed Coast Range uplift. Left-oblique northeast-trending faults and conjugate northwest-trending right-oblique faults offset Grande Ronde and Frenchman Springs dikes and sills. This conjugate fault pattern may reflect oblique east-west convergence between the North American and Juan de Fuca plates. The Silver Point mudstones and Oswald West mudstones have high total organic carbon contents, up to 5.5%, but are thermally immature and may act only as a source for biogenic gas(?) in the subsurface. Suitable reservoir rocks, such as the gas-producing upper Eocene Cowlitz Formation C & W sandstone, may pinch out before reaching the Green Mountain-Young's River area and are yet to be penetrated by exploration drilling. Post-middle Miocene fault traps abound in the area, although these faults might also breach subsurface natural gas reservoirs in the Green Mountain-Young's River area. Close

• 29. [Article] Memoirs of William Jasper Gilstrap

  In this memoir, by alumnus and Zoology Department instructor William J. Gilstrap, the author details various aspects of his life, including: childhood in Missouri, student experience at Oregon Agricultural ...

  Citation × Citation Citation Abstract Copy Title: Memoirs of William Jasper Gilstrap Author: Gilstrap, William J. In this memoir, by alumnus and Zoology Department instructor William J. Gilstrap, the author details various aspects of his life, including: childhood in Missouri, student experience at Oregon Agricultural College (OAC) in the 1890s, and his medical practice in various Oregon locales. Gilstrap also describes in this narrative the origins of his ancestorial lineage dating back to mid-18th century Scotland. The communities mentioned in the memoirs where Gilstrap practiced medicine include St. Johns, Sheridan, and the Grand Ronde Indian Reservation. Passages relating to OAC include descriptions of Gilstrap's participation in college oratorical contests, military service for the college, coursework taken in veterinary studies, his work in the Zoology Department, association with Professor Arthur Cordley, and living in rental houses adjacent to campus at the time. In this memoirs, Gilstrap also devotes chapters to his thoughts on health care provision in the Portland area and the spectre of "socialized medicine," dealing with allergic reactions, investing in the stock market, and "human nature." Title: Memoirs of William Jasper Gilstrap Author: Gilstrap, William J. In this memoir, by alumnus and Zoology Department instructor William J. Gilstrap, the author details various aspects of his life, including: childhood in Missouri, student experience at Oregon Agricultural College (OAC) in the 1890s, and his medical practice in various Oregon locales. Gilstrap also describes in this narrative the origins of his ancestorial lineage dating back to mid-18th century Scotland. The communities mentioned in the memoirs where Gilstrap practiced medicine include St. Johns, Sheridan, and the Grand Ronde Indian Reservation. Passages relating to OAC include descriptions of Gilstrap's participation in college oratorical contests, military service for the college, coursework taken in veterinary studies, his work in the Zoology Department, association with Professor Arthur Cordley, and living in rental houses adjacent to campus at the time. In this memoirs, Gilstrap also devotes chapters to his thoughts on health care provision in the Portland area and the spectre of "socialized medicine," dealing with allergic reactions, investing in the stock market, and "human nature." Close

• 30. [Article] Pacific lamprey research and restoration : 1997 annual report

  Based on oral interviews with tribal informants, current and former state and federal fisheries personnel, review of records and literature, and presence/absence sampling, it is apparent that Pacific lamprey ...

  Citation × Citation Citation Abstract Copy Title: Pacific lamprey research and restoration : 1997 annual report Author: Jackson, Aaron D., Close, David A., Oregon Cooperative Fishery Research Unit, Confederated Tribes of the Umatilla Indian Reservation in Oregon., Columbia River Inter-Tribal Fish Commission., Hatch, Douglas R., Li, Hiram W. Based on oral interviews with tribal informants, current and former state and federal fisheries personnel, review of records and literature, and presence/absence sampling, it is apparent that Pacific lamprey were once abundant in ceded area streams of the Umatilla Indian Reservation (John Day, Umatilla, Walla Walla, Tucannon, and Grande Ronde subbasins). Current population levels appear severely depressed in all subbasins except possibly the John Day, which could be classified as depressed. The most probable reasons for population declines include: dams, chemical treatment activities, declining habitat quality (e.g. high water temperatures, poor water quality, low instream flows), and angle-iron in fishways to prevent lamprey passage. Title: Pacific lamprey research and restoration : 1997 annual report Author: Jackson, Aaron D., Close, David A., Oregon Cooperative Fishery Research Unit, Confederated Tribes of the Umatilla Indian Reservation in Oregon., Columbia River Inter-Tribal Fish Commission., Hatch, Douglas R., Li, Hiram W. Based on oral interviews with tribal informants, current and former state and federal fisheries personnel, review of records and literature, and presence/absence sampling, it is apparent that Pacific lamprey were once abundant in ceded area streams of the Umatilla Indian Reservation (John Day, Umatilla, Walla Walla, Tucannon, and Grande Ronde subbasins). Current population levels appear severely depressed in all subbasins except possibly the John Day, which could be classified as depressed. The most probable reasons for population declines include: dams, chemical treatment activities, declining habitat quality (e.g. high water temperatures, poor water quality, low instream flows), and angle-iron in fishways to prevent lamprey passage. Close

• 31. [Article] Stratigraphy, sedimentology, and petrology of neogene rocks in the Deschutes basin, central Oregon : a record of continental-margin volcanism and its influence on fluvial sedimentation in an arc-adjacent basin

  Neogene rocks of the Deschutes basin include the middle Miocene Columbia River Basalt Group and Simtustus Formation, and late Miocene to early Pliocene Deschutes Formation. Assignment of Prineville chemical-type ...

  Citation × Citation Citation Abstract Copy Title: Stratigraphy, sedimentology, and petrology of neogene rocks in the Deschutes basin, central Oregon : a record of continental-margin volcanism and its influence on fluvial sedimentation in an arc-adjacent basin Author: Smith, Gary Allen Neogene rocks of the Deschutes basin include the middle Miocene Columbia River Basalt Group and Simtustus Formation, and late Miocene to early Pliocene Deschutes Formation. Assignment of Prineville chemical-type flows to the Grande Ronde Basalt of the Columbia River Basalt Group is based upon correlation of these lavas from their type area, through the Deschutes basin, and onto the Columbia Plateau where they have been previously mapped as Grande Ronde Basalt. Simtustus Formation is a newly defined unit intercalated with and conformable upon these basalts and is unconformably overlain by Deschutes Formation. Burial of mature topography by middle Miocene basalts raised local base levels and initiated aggradation by low-gradient streams within the basin represented by the tuffaceous sandstones and mudstones of the Simtustus Formation. These sediments are enriched in pyroclastic constituents relative to contemporary Western Cascades volcanics reflecting preferential incorporation of easily eroded and more widespread pyroclastic debris in distal sedimentary sequences compared to epiclastic contributions from lavas. Following a 5 to 7 m.y. hiatus, aggradation was renewed at about 7.5 Ma when coarse-grained volcanogenic sediments, lava flows and ignimbrites from the early High Cascades entered the basin for 2 m.y. The proximal Deschutes Formation is primarily basalt and basaltic andesite lava flows but andesite to rhyolite ignimbrites are the primary volcanic constitutents in the sedimentary-dominated section farther east. Deposition on a broad, eastward-tapering alluvial plain was by debris flows, sheetfloods, and hyperconcentrated flood flows. Episodic aggradation correlates to periods of sediment influx following eruptions' of widespread pyroclastic debris and was separated by periods of incision. The abundance of basalts, combined with the paucity of hydrous minerals and FeO and TiO₂ enrichment in intermediate lavas characterize early High Cascade yolcanics as atypical for convergent-margin arcs. These petrologic characteristics are consistent with high-level fractionation in an extensional regime. Extension culminated in the development of an intra-arc graben which ended Deschutes Formation deposition by structurally isolating the basin from the High Cascade source area. Intra-arc extension may represent invasion of Basin and Range tectonism into the Cascades, or may relate to plate-margin processes, particularly decreasing convergence rate and highly oblique convergence vector. Title: Stratigraphy, sedimentology, and petrology of neogene rocks in the Deschutes basin, central Oregon : a record of continental-margin volcanism and its influence on fluvial sedimentation in an arc-adjacent basin Author: Smith, Gary Allen Neogene rocks of the Deschutes basin include the middle Miocene Columbia River Basalt Group and Simtustus Formation, and late Miocene to early Pliocene Deschutes Formation. Assignment of Prineville chemical-type flows to the Grande Ronde Basalt of the Columbia River Basalt Group is based upon correlation of these lavas from their type area, through the Deschutes basin, and onto the Columbia Plateau where they have been previously mapped as Grande Ronde Basalt. Simtustus Formation is a newly defined unit intercalated with and conformable upon these basalts and is unconformably overlain by Deschutes Formation. Burial of mature topography by middle Miocene basalts raised local base levels and initiated aggradation by low-gradient streams within the basin represented by the tuffaceous sandstones and mudstones of the Simtustus Formation. These sediments are enriched in pyroclastic constituents relative to contemporary Western Cascades volcanics reflecting preferential incorporation of easily eroded and more widespread pyroclastic debris in distal sedimentary sequences compared to epiclastic contributions from lavas. Following a 5 to 7 m.y. hiatus, aggradation was renewed at about 7.5 Ma when coarse-grained volcanogenic sediments, lava flows and ignimbrites from the early High Cascades entered the basin for 2 m.y. The proximal Deschutes Formation is primarily basalt and basaltic andesite lava flows but andesite to rhyolite ignimbrites are the primary volcanic constitutents in the sedimentary-dominated section farther east. Deposition on a broad, eastward-tapering alluvial plain was by debris flows, sheetfloods, and hyperconcentrated flood flows. Episodic aggradation correlates to periods of sediment influx following eruptions' of widespread pyroclastic debris and was separated by periods of incision. The abundance of basalts, combined with the paucity of hydrous minerals and FeO and TiO₂ enrichment in intermediate lavas characterize early High Cascade yolcanics as atypical for convergent-margin arcs. These petrologic characteristics are consistent with high-level fractionation in an extensional regime. Extension culminated in the development of an intra-arc graben which ended Deschutes Formation deposition by structurally isolating the basin from the High Cascade source area. Intra-arc extension may represent invasion of Basin and Range tectonism into the Cascades, or may relate to plate-margin processes, particularly decreasing convergence rate and highly oblique convergence vector. Close

• 32. [Article] Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A.

  Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) ...

  Citation × Citation Citation Abstract Copy Title: Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A. Author: Sheoships, Gabe Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) since time immemorial to guide their ways of life, transmitting cultural values and natural history to further generational knowledge. Pacific lamprey are in decline throughout their range, and have historically been disregarded in western science. The Willamette River Basin, Oregon, U.S.A currently supports a traditional harvest location, Willamette Falls, which continues to persist, despite great losses in adjacent basins and remains a harvest stronghold amongst Columbia River Basin Tribes. To further understand Pacific lamprey, we utilized both Indigenous knowledge and western science to gain information that would aid recovery. My first goal was to determine traditional ecological knowledge and the cultural values of Pacific lamprey to provide guidance for future conservation planning. My second goal was to evaluate the fine scale habitat characteristics of larval Pacific lamprey. To determine tribal values for the purpose of informing conservation planning of Pacific lamprey, I used: 1) oral history interviews of tribal elders, and 2) questionnaires distributed across entire adult (18 years and older) tribal populations. We conducted semi-structured interviews with tribal elders to gain insights into the biology, distribution, and cultural value of lamprey. I interviewed 32 tribal elders, 11 from the Grand Ronde, 10 from the Siletz, and 11 from the Umatilla. To understand modern fishing practices and current values of lamprey, I distributed a standardized questionnaire (n = 753) to a sample of each adult (18 years and older) tribal population, and received a total of 188 responses total: 38 from the Grand Ronde, 60 from the Siletz, and 90 from the Umatilla. From my interviews, I found that each tribe has noticed a decline in Pacific lamprey populations within their ceded areas, and has witnessed traditional harvest locations lost due to population declines and/or anthropogenic damage, leaving Willamette Falls as the sole harvest site for the three tribes. Questionnaire results showed that the strongest issues relating to the traditional usage of Pacific lamprey amongst each tribe are cultural awareness, harvest accessibility, and Pacific lamprey populations. I evaluated two fine scale habitat associations of larval Pacific lamprey in the Willamette River Basin to understand the association of stream sediment and larval abundance. Study objectives were to: 1) evaluate the substrate size most closely associated with larval abundance, and 2) to evaluate the influence of organic material upon larval abundance. We used a backpack electrofisher to enumerate larval lamprey in six wadeable Willamette River tributaries, using a nested two-pass sample design at a lower, middle, and upper reach (each reach composed of ten 1-m² quadrats). Stream sediment cores were collected for subsequent determination of particle size and organic composition content. I used particle size sieve analysis to estimate dominant substrate size class per sample, from the following size classes: silt (< 0.063 mm), very fine sand (0.063–0.125 mm), fine sand (0.125-0.25 mm), medium fine sand (0.25-0.50 mm), coarse sand (0.50-1.0 mm), very coarse sand (1.0-2.36 mm), and fine gravel (>2.36 mm). I analyzed organic content by loss of weight through combustion. Larvae were present in 17 of 18 reaches (94%) 18), but only detected in 37% of the quadrats. Larval Pacific lamprey abundance was highest in habitats with predominantly medium fine sand (0.25-0.50 mm) substrate. I fit negative binomial mixed models using parameters for sediment depth, percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. My top model consisted of percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. At the fine scale, substrate characteristics were associated with the abundance of larval Pacific lamprey. Appropriate conservation measures should be taken to address the restoration of Pacific lamprey, activities that promote natural river flow and distribution of sediment could be of benefit. Efforts that educate mainstream society should be implemented to reduce further species decline. With the continued decline of Pacific lamprey, there is potential for further degradation of tribal cultural values. Conservation work that promotes the restoration of Pacific lamprey is crucial to the tradition and culture of the Grand Ronde, Siletz, and Umatilla Tribes. Title: Pacific lamprey Entosphenus tridentatus : integrating traditional ecological knowledge and contemporary values into conservation planning, and stream substrate associations with larval abundance in the Willamette River Basin, Oregon, U.S.A. Author: Sheoships, Gabe Pacific lamprey Entosphenus tridentatus is a valuable icon and traditional food source for Indigenous people of western North America. Native Americans have utilized traditional ecological knowledge (TEK) since time immemorial to guide their ways of life, transmitting cultural values and natural history to further generational knowledge. Pacific lamprey are in decline throughout their range, and have historically been disregarded in western science. The Willamette River Basin, Oregon, U.S.A currently supports a traditional harvest location, Willamette Falls, which continues to persist, despite great losses in adjacent basins and remains a harvest stronghold amongst Columbia River Basin Tribes. To further understand Pacific lamprey, we utilized both Indigenous knowledge and western science to gain information that would aid recovery. My first goal was to determine traditional ecological knowledge and the cultural values of Pacific lamprey to provide guidance for future conservation planning. My second goal was to evaluate the fine scale habitat characteristics of larval Pacific lamprey. To determine tribal values for the purpose of informing conservation planning of Pacific lamprey, I used: 1) oral history interviews of tribal elders, and 2) questionnaires distributed across entire adult (18 years and older) tribal populations. We conducted semi-structured interviews with tribal elders to gain insights into the biology, distribution, and cultural value of lamprey. I interviewed 32 tribal elders, 11 from the Grand Ronde, 10 from the Siletz, and 11 from the Umatilla. To understand modern fishing practices and current values of lamprey, I distributed a standardized questionnaire (n = 753) to a sample of each adult (18 years and older) tribal population, and received a total of 188 responses total: 38 from the Grand Ronde, 60 from the Siletz, and 90 from the Umatilla. From my interviews, I found that each tribe has noticed a decline in Pacific lamprey populations within their ceded areas, and has witnessed traditional harvest locations lost due to population declines and/or anthropogenic damage, leaving Willamette Falls as the sole harvest site for the three tribes. Questionnaire results showed that the strongest issues relating to the traditional usage of Pacific lamprey amongst each tribe are cultural awareness, harvest accessibility, and Pacific lamprey populations. I evaluated two fine scale habitat associations of larval Pacific lamprey in the Willamette River Basin to understand the association of stream sediment and larval abundance. Study objectives were to: 1) evaluate the substrate size most closely associated with larval abundance, and 2) to evaluate the influence of organic material upon larval abundance. We used a backpack electrofisher to enumerate larval lamprey in six wadeable Willamette River tributaries, using a nested two-pass sample design at a lower, middle, and upper reach (each reach composed of ten 1-m² quadrats). Stream sediment cores were collected for subsequent determination of particle size and organic composition content. I used particle size sieve analysis to estimate dominant substrate size class per sample, from the following size classes: silt (< 0.063 mm), very fine sand (0.063–0.125 mm), fine sand (0.125-0.25 mm), medium fine sand (0.25-0.50 mm), coarse sand (0.50-1.0 mm), very coarse sand (1.0-2.36 mm), and fine gravel (>2.36 mm). I analyzed organic content by loss of weight through combustion. Larvae were present in 17 of 18 reaches (94%) 18), but only detected in 37% of the quadrats. Larval Pacific lamprey abundance was highest in habitats with predominantly medium fine sand (0.25-0.50 mm) substrate. I fit negative binomial mixed models using parameters for sediment depth, percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. My top model consisted of percentage of medium fine sand (0.25-0.50 mm), organic material and a random effect for basin. At the fine scale, substrate characteristics were associated with the abundance of larval Pacific lamprey. Appropriate conservation measures should be taken to address the restoration of Pacific lamprey, activities that promote natural river flow and distribution of sediment could be of benefit. Efforts that educate mainstream society should be implemented to reduce further species decline. With the continued decline of Pacific lamprey, there is potential for further degradation of tribal cultural values. Conservation work that promotes the restoration of Pacific lamprey is crucial to the tradition and culture of the Grand Ronde, Siletz, and Umatilla Tribes. Close

• 33. [Article] Foodways at Fort Yamhill, 1856-1866 : an archaeological and archival perspective

  Fort Yamhill, located in the eastern foothills of the Oregon Coast Range near modern day Grand Ronde, Oregon, was a U.S. Army post established in March 1856 as part of a three fort system to guard the ...

  Citation × Citation Citation Abstract Copy Title: Foodways at Fort Yamhill, 1856-1866 : an archaeological and archival perspective Author: Eichelberger, Justin E. Fort Yamhill, located in the eastern foothills of the Oregon Coast Range near modern day Grand Ronde, Oregon, was a U.S. Army post established in March 1856 as part of a three fort system to guard the newly established Coast Reservation and to provide a Union presence in the state during the American Civil War. This thesis examines U.S. Army foodways at Fort Yamhill and provides a basis for future work on the subject. Combining the archaeological and archival data from the site provided the unique opportunity to examine the foodways of the mid-19th century U.S. Army holistically. Results of this research suggests that although the soldiers stationed at Fort Yamhill were at the end of long supply lines and far from populated cities, the diet consumed by the soldiers was adequate and often abundant. Procuring subsistence stores from many sources soldiers were able to procure a steady and healthful diet and often had the opportunity to display social and economic status through their patterns of food consumption. Title: Foodways at Fort Yamhill, 1856-1866 : an archaeological and archival perspective Author: Eichelberger, Justin E. Fort Yamhill, located in the eastern foothills of the Oregon Coast Range near modern day Grand Ronde, Oregon, was a U.S. Army post established in March 1856 as part of a three fort system to guard the newly established Coast Reservation and to provide a Union presence in the state during the American Civil War. This thesis examines U.S. Army foodways at Fort Yamhill and provides a basis for future work on the subject. Combining the archaeological and archival data from the site provided the unique opportunity to examine the foodways of the mid-19th century U.S. Army holistically. Results of this research suggests that although the soldiers stationed at Fort Yamhill were at the end of long supply lines and far from populated cities, the diet consumed by the soldiers was adequate and often abundant. Procuring subsistence stores from many sources soldiers were able to procure a steady and healthful diet and often had the opportunity to display social and economic status through their patterns of food consumption. Close

• 34. [Article] Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection

  Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An ...

  Citation × Citation Citation Abstract Copy Title: Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection Author: Mayer, Kent Corey Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An experiment was performed to see if mature male spring chinook salmon parr could be reconditioned after hand-spawning and spawned in successive years. The mature male parr were part of a 1997 and 1998 cohort of captive broodstock from the Grande Ronde River Basin in Oregon. Force-feeding was combined with volitional feeding in an attempt to inhibit senescence and increase survival time after spawning. The viscerosomatic index, fat and protein contents increased with survival time after spawning for both cohorts. There was a significant relationship between percent weight change and survival time for the 1997 cohort (p<0.001). Force-feeding had no effect on survival time after spawning for the 1997 cohort (p=0.074) or the 1998 cohort (p=0.178). Fat content, weight gain and survival time indicated that the reconditioning process was observable in the 1997 cohort at 77 days after spawning and was cyclical, resulting in a physiological response which allowed male chinook salmon to spawn in successive years. Fertilization trials with three reconditioned males yielded a fertilization success rate of 96.9% compared to 95.7% for 4-year old, anadromous male spring chinook salmon (p=0.152), measured as production of eyed-embryos. This experiment provides new knowledge of plasticity in the reproductive biology of male, stream-type, spring chinook salmon. Reconditioning and spawning male chinook salmon parr in successive years could be used to help maximize genetic diversity and aid in the recovery of endangered Oncorhynchus populations. Title: Spawning chinook salmon (Oncorhynchus tshawytscha) two years in a row : reconditioning for repeated gamete collection Author: Mayer, Kent Corey Spring chinook salmon, Oncorhynchus tshawytscha, in the Snake River Basin are listed as endangered under the Endangered Species Act. The typical life history of spring chinook salmon is semelparous. An experiment was performed to see if mature male spring chinook salmon parr could be reconditioned after hand-spawning and spawned in successive years. The mature male parr were part of a 1997 and 1998 cohort of captive broodstock from the Grande Ronde River Basin in Oregon. Force-feeding was combined with volitional feeding in an attempt to inhibit senescence and increase survival time after spawning. The viscerosomatic index, fat and protein contents increased with survival time after spawning for both cohorts. There was a significant relationship between percent weight change and survival time for the 1997 cohort (p<0.001). Force-feeding had no effect on survival time after spawning for the 1997 cohort (p=0.074) or the 1998 cohort (p=0.178). Fat content, weight gain and survival time indicated that the reconditioning process was observable in the 1997 cohort at 77 days after spawning and was cyclical, resulting in a physiological response which allowed male chinook salmon to spawn in successive years. Fertilization trials with three reconditioned males yielded a fertilization success rate of 96.9% compared to 95.7% for 4-year old, anadromous male spring chinook salmon (p=0.152), measured as production of eyed-embryos. This experiment provides new knowledge of plasticity in the reproductive biology of male, stream-type, spring chinook salmon. Reconditioning and spawning male chinook salmon parr in successive years could be used to help maximize genetic diversity and aid in the recovery of endangered Oncorhynchus populations. Close

• 35. [Article] The Oregon Tribal Archives Institute: Providing a Professional Development and Networking Opportunity for Oregon’s Tribal Communities

  Presenters: Natalia Fernández, Oregon State University; David Lewis, Confederated Tribes of the Grand Ronde Community of Oregon; and Jennifer O’Neal, University of Oregon. The session chair was Larry Landis, ...

  Citation × Citation Citation Abstract Copy Title: The Oregon Tribal Archives Institute: Providing a Professional Development and Networking Opportunity for Oregon’s Tribal Communities Author: Fernández, Natalia, O'Neal, Jennifer, Lewis, David Presenters: Natalia Fernández, Oregon State University; David Lewis, Confederated Tribes of the Grand Ronde Community of Oregon; and Jennifer O’Neal, University of Oregon. The session chair was Larry Landis, Oregon State University Title: The Oregon Tribal Archives Institute: Providing a Professional Development and Networking Opportunity for Oregon’s Tribal Communities Author: Fernández, Natalia, O'Neal, Jennifer, Lewis, David Presenters: Natalia Fernández, Oregon State University; David Lewis, Confederated Tribes of the Grand Ronde Community of Oregon; and Jennifer O’Neal, University of Oregon. The session chair was Larry Landis, Oregon State University Close

• 36. [Article] A resource survey of river energy and low-head hydroelectric power potential in Oregon

  The project was funded by the United States Department of Energy. Contract No. EG-77-S-07-1691 through the Idaho Water Resources Research Institute.

  Citation × Citation Citation Abstract Copy Title: A resource survey of river energy and low-head hydroelectric power potential in Oregon Author: Klingeman, Peter C., Oregon State University. Water Resources Research Institute, Idaho Water Resources Research Institute, State of Washington Water Research Center, Montana University Joint Water Resources Research Center The project was funded by the United States Department of Energy. Contract No. EG-77-S-07-1691 through the Idaho Water Resources Research Institute. Title: A resource survey of river energy and low-head hydroelectric power potential in Oregon Author: Klingeman, Peter C., Oregon State University. Water Resources Research Institute, Idaho Water Resources Research Institute, State of Washington Water Research Center, Montana University Joint Water Resources Research Center The project was funded by the United States Department of Energy. Contract No. EG-77-S-07-1691 through the Idaho Water Resources Research Institute. Close

• 37. [Article] An enthnobotanical analysis of basketry

  The focus of my thesis is ethnobotany which seeks to examine botanical resources and their context within particular cultures. My ethnographic research identifies and interprets the cultural processes ...

  Citation × Citation Citation Abstract Copy Title: An enthnobotanical analysis of basketry Author: Fluharty, Suzanne M. The focus of my thesis is ethnobotany which seeks to examine botanical resources and their context within particular cultures. My ethnographic research identifies and interprets the cultural processes woven into Oregon's coastal basketry through spirituality, environmental habitats, and utilized plant species. This is augmented with botanical research addressing the question of whether the basketry materials utilized by the diverse population of Pacific Northwest Tribes, can be identified to species through microscopic analysis. Comparative epidermal and cuticle techniques are tested for diagnostic potential in a pilot test of 19 species sampled from existing populations on Oregon's coast, from Tillamook Bay in the north to the Coquille River in the south. It builds on and seeks to integrate the knowledge of which native plant species have been historically utilized as fiber materials for baskets, mats, cordage and other woven articles by various Oregon and Northern California bands and tribes that are currently represented by the Coquille Indian Tribe, the Confederated Tribes of Grande Ronde, and the Confederated Tribes of Siletz. My research consists of three phases; 1) historic and ethnographic research, 2) standard taxonomic identification of targeted wetland species through collection of living plants, and 3) a comparative study of the cuticular surface of plants using scanning electron microscopy. My results confirm that epidermal and cuticular characteristics are diagnostic; however, the range of variability in the surface wax is extreme in the 19 selected wetland plants and can often be an impediment to the analysis of underlying characteristics. Furthermore, my results have a limited scope for the identification of basketry materials. The comparative process appears to be valuable in excluding known and identified botanical materials, but not in specifying which species is represented due to the range of possible and unknown species. With more comprehensive libraries of analyzed species, the gap between the eliminated species and the identified ones would narrow. Therefore, the identification of basketry materials to species is possible using the processes considered in this test pilot study but the number of analyzed species would need to be greatly expanded. Title: An enthnobotanical analysis of basketry Author: Fluharty, Suzanne M. The focus of my thesis is ethnobotany which seeks to examine botanical resources and their context within particular cultures. My ethnographic research identifies and interprets the cultural processes woven into Oregon's coastal basketry through spirituality, environmental habitats, and utilized plant species. This is augmented with botanical research addressing the question of whether the basketry materials utilized by the diverse population of Pacific Northwest Tribes, can be identified to species through microscopic analysis. Comparative epidermal and cuticle techniques are tested for diagnostic potential in a pilot test of 19 species sampled from existing populations on Oregon's coast, from Tillamook Bay in the north to the Coquille River in the south. It builds on and seeks to integrate the knowledge of which native plant species have been historically utilized as fiber materials for baskets, mats, cordage and other woven articles by various Oregon and Northern California bands and tribes that are currently represented by the Coquille Indian Tribe, the Confederated Tribes of Grande Ronde, and the Confederated Tribes of Siletz. My research consists of three phases; 1) historic and ethnographic research, 2) standard taxonomic identification of targeted wetland species through collection of living plants, and 3) a comparative study of the cuticular surface of plants using scanning electron microscopy. My results confirm that epidermal and cuticular characteristics are diagnostic; however, the range of variability in the surface wax is extreme in the 19 selected wetland plants and can often be an impediment to the analysis of underlying characteristics. Furthermore, my results have a limited scope for the identification of basketry materials. The comparative process appears to be valuable in excluding known and identified botanical materials, but not in specifying which species is represented due to the range of possible and unknown species. With more comprehensive libraries of analyzed species, the gap between the eliminated species and the identified ones would narrow. Therefore, the identification of basketry materials to species is possible using the processes considered in this test pilot study but the number of analyzed species would need to be greatly expanded. Close

• 38. [Article] Cable thinning in young forests with average DBH of 5-8 inches : a case study

  This paper describes the results of a time-study conducted near Grand Ronde, Oregon, to determine the production rates and total harvesting costs of a cable thinning in a young stand. The stand had a species ...

  Citation × Citation Citation Abstract Copy Title: Cable thinning in young forests with average DBH of 5-8 inches : a case study Author: Gabrielli, Robert Michael This paper describes the results of a time-study conducted near Grand Ronde, Oregon, to determine the production rates and total harvesting costs of a cable thinning in a young stand. The stand had a species mix of 48 percent western hemlock (Tsuga. heterophylla- (Raf.) Sarg.), 45 percent Douglas-fir (Pseudotsuga meuziesil (Mirb.) Franco), and 7 percent white fir (Abies concolor (Gord. & Fiend.) Lindi.). The stand had an average age of 33 years, with a mean dbh of the total stand (over 1.5 inches (3.8i cm) dbh) of 5.7 inches (14.48 cm). The mean dbh of the merchantable stems (over 6 inches (15.84 cm) dbh) was 8.3 inches. The yarder belonged to the small size class of yarders, and was rigged with a live skyline system using a selfclamping, manual slack-puliing carriage. Three hooking techniques consisting of three chokers with sliders, presetting three ring chokers andusing a toggle hook, and flying six ring chokers per turn were compared on a production basis. Regression equations were developed for the individual elements of the yarding cycles and for total cycle times ftr each hooking technique. Results indicate that there is no significant difference between the production rates of three chokers and sliders compared with three preset ring chokers and a toggle hook. There was a significant difierence between the production rates when using the three chokers and sliders compared with using six ring chokers and a toggle hook. The six ring chokers and toggle hook was about 13 percent faster per MBP. The total harvesting cost was compared with the mill value of the timber. The total harvesting cost included felling, limbing, and bucking cost, equipment move-in and move-out cost, yarding cost, loading cost, and hauling cost. Not included in the harvesting cost was road costs, engineering and layout costs, timber tax costs, or any profit and risk costs. The total harvesting cost came to $227.90 per MBP. The weighted average mill price for the logs was $250.24 per MBP. Title: Cable thinning in young forests with average DBH of 5-8 inches : a case study Author: Gabrielli, Robert Michael This paper describes the results of a time-study conducted near Grand Ronde, Oregon, to determine the production rates and total harvesting costs of a cable thinning in a young stand. The stand had a species mix of 48 percent western hemlock (Tsuga. heterophylla- (Raf.) Sarg.), 45 percent Douglas-fir (Pseudotsuga meuziesil (Mirb.) Franco), and 7 percent white fir (Abies concolor (Gord. & Fiend.) Lindi.). The stand had an average age of 33 years, with a mean dbh of the total stand (over 1.5 inches (3.8i cm) dbh) of 5.7 inches (14.48 cm). The mean dbh of the merchantable stems (over 6 inches (15.84 cm) dbh) was 8.3 inches. The yarder belonged to the small size class of yarders, and was rigged with a live skyline system using a selfclamping, manual slack-puliing carriage. Three hooking techniques consisting of three chokers with sliders, presetting three ring chokers andusing a toggle hook, and flying six ring chokers per turn were compared on a production basis. Regression equations were developed for the individual elements of the yarding cycles and for total cycle times ftr each hooking technique. Results indicate that there is no significant difference between the production rates of three chokers and sliders compared with three preset ring chokers and a toggle hook. There was a significant difierence between the production rates when using the three chokers and sliders compared with using six ring chokers and a toggle hook. The six ring chokers and toggle hook was about 13 percent faster per MBP. The total harvesting cost was compared with the mill value of the timber. The total harvesting cost included felling, limbing, and bucking cost, equipment move-in and move-out cost, yarding cost, loading cost, and hauling cost. Not included in the harvesting cost was road costs, engineering and layout costs, timber tax costs, or any profit and risk costs. The total harvesting cost came to $227.90 per MBP. The weighted average mill price for the logs was $250.24 per MBP. Close

• 39. [Article] Geology of the Elsie-lower Nehalem River area, south-central Clatsop and northern Tillamook counties, northwestern Oregon

  The middle Eocene Tillamook Volcanics form the oldest rock unit in the Elsie-lower Nehalem River area. K-Ar age determinations and age constraints imposed by foraminiferal and calcareous nannofossil assemblages ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Elsie-lower Nehalem River area, south-central Clatsop and northern Tillamook counties, northwestern Oregon Author: Mumford, Daniel Franklin The middle Eocene Tillamook Volcanics form the oldest rock unit in the Elsie-lower Nehalem River area. K-Ar age determinations and age constraints imposed by foraminiferal and calcareous nannofossil assemblages of overlying sedimentary strata indicate an absolute age of about 42 Ma for the uppermost Tillamook Volcanics. Major oxide values indicate that the upper Tillamook Volcanics are highly fractionated high Fe-Ti tholeiitic basalts and basaltic andesites. These volcanics were erupted in a developing forearc under an extensional plate tectonic setting and formed a moderately large oceanic island. These subaerial flows are predominantly aphyric to plagioclase-augite porphyritic and have a pilotaxitic flow texture. Epochs of both normal and reverse magnetic polarity are recorded. Thermal subsidence related to the end of the volcanism resulted in deposition of the transgressive late Eocene Hamlet formation over the "Tillamook island". The informal Hamlet formation consists of three members. From oldest to youngest they are: the Roy Creek member, the Sunset Highway member, and the Sweet Home Creek member. Three lithofacies are present in the Roy Creek member. The stratigraphically lowest of these consists of basaltic boulder-pebble conglomerate and locally fossiliferous pebbly basaltic sandstones which were deposited in a high energy nearshore environment around rocky basaltic headlands and sea stacks of the Tillamook Volcanics. Molluscan fossils in this lithofacies are correlative to the middle to late Eocene "CowlitzCoaledo" fauna. Successively overlying lithofacies are a very coarseto coarse-grained shallow marine basaltic sandstone lithofacies and a medium- to fine-grained basaltic sandstone lithofacies. This fining upward sequenced documents progressive deepening of the depositional basin. Framework clasts in all three Roy Creek member lithofacies were predominantly derived from the Tillamook Volcanics. Pore-filling diagenetic chlorite, smectite (nontronite), calcite, and zeolite (clinoptilolite and heulandite) cements severely reduce the porosity of Roy Creek member sandstones. The Sunset Highway member of the Hamlet formation conformably overlies the Roy Creek member in eastern Clatsop and western Columbia counties and pinches out to the west at about the longitude of the Nehalem River in T. 4 N., R. 8 W.. The Sunset Highway member is predominantly composed of interbedded micaceous arkosic sandstone, lithic arkose, and muddy micaceous arkosic siltstone with a few beds of basaltic sandstone and basaltic debris flow breccias. The dominant micaceous arkosic composition of the Sunset Highway member reflects a distant extrabasinal granitic-metamorphic provenance and contrasts with that of the locally derived underlying basaltic Roy Creek member. Low angle trough cross-bedding, hummocky bedding, and microcross-laminations in fine to medium-grained arkosic sandstones are interpreted to have been produced by large storm-generated waves and on a high energy inner shelf. Thin interbeds of bioturbated mudstone and mollusc-bearing bioturbated sandstones formed during periods of fairweather conditions and during lower sedimentation rates. Rare matrix supported, basaltic debris-flow breccias and basaltic sandstones were derived from nearby basaltic headlands and by rivers draining the Tillamook Volcanics. Minor secondary intraparticle porosity occurs with some primary intergranular porosity in relatively matrix-free Sunset Highway member arkosic sandstones. However, much of the porosity and permeability of these potential sandstones has been reduced by diagenetic smectite coatings on framework grains and potassium feldspar overgrowths of feldspars. The mudstone-dominated Sweet Home Creek member was conformably deposited on the Sunset Highway member in eastern Clatsop and western Columbia counties. In western Clatsop County the Sweet Home Creek member directly and conformably overlies the Roy Creek member due to pinch out of the Sunset Highway member. Upper Narizian to lowermost Refugian benthic foraminiferal assemblages from this unit indicate outer shelf to upper slope sedimentation and continued subsidence of the depositional (Astoria) basin. Micromicaceous and carbonaceous silty mudatone dominates this unit but thin-bedded micaceous arkosic turbidite sandstones are present in the lower part, and rare, thin basaltic turbidites are present in the upper half. X-ray diffraction analysis shows that the dominant clay minerals in the Sweet Home Creek member niudstone are smectite (montmorillonite), kaolinite, and illite. The Cole Mountain basalt (informal) intrudes and locally overlies the Sweet Home Creek member. This caic-alkaline basaltic andesite is thought to have formed in a compressional plate tectonic regime and been emplaced on the outer shelf and upper slope as shallow irregular sills and dikes and minor submarine pillow basalt-hyaloclastite complexes. Siliceous nodules associated with pillowed units locally contains a few per cent pyrite and are associated with small areas of high-grade supergene copper-silver mineralization. The normally polarized Cole Mountain basalt is chemically, petrographically, and lithologically distinct from the Tillamook Volcanics and Grande Ronde Basalt of the Columbia River Basalt Group. The uppermost Narizian and Refugian (late Eocene) Jewell member of the Keasey Formation disconformably overlies the Cole Mountain basalt and Sweet Home Creek member. A thin basal glauconitic sandstone-siltstone reflects a period of reduced sedimentation under slightly reducing conditions and marks the disconformity. The unit primarily consists of laminated to thin bedded tuffaceous mudstone with a few thin tuff beds, small micaceous arkosic sandstone channels and clastic dikes. Clay minerals in the Jewell member are dominated by smectite (montmorillonite), with minor kaolinite and illite (degraded mica) in the lower part of the unit. Benthic foraminiferal assemblages in the unit indicate bathyal or slope depths and have been assigned to the lower Refugian to upper Narizian stages. In the middle Miocene, irregular dikes and sills of the Grande Ronde Basalt of the Columbia River Basalt Group intruded the late Eocene sedimentary strata in the thesis area. Two magneto-chemical types of Grande Ronde Basalt, N2/low MgO-low Ti02 and N2/ high MgO, were identified in the thesis area. These were geochemically and magnetically correlated to subaerial flows of magneto-chemical types IA and 5A of Mangan and others (1986) on the Columbia Plateau. The intrusions or invasive flows are interpreted to have been derived from voluminous plateau eruptions by invasion into soft, unconsolidated Neogene sediments at the marine/coast interface and then into the more brittle but ductile Paleogene strata of the area as first proposed by Beeson and others (1979). Uplift of the Coast Range was initiated in the late Miocene as a result of rapid offshore underthrusting in the subduction zone (Snavely and others, 1983). This has resulted in subaerial erosion and exposure of the faulted and gently folded forearc ridge and deposition of Quaternary alluvial gravels and sands along major rivers and creek in the thesis area. The dominant structural features of the Elsie-lower Nehalem River area are generally down-to-the-north, east-west-trending high angle faults with oblique offset and a conjugate set of oblique slip northwest-trending right-lateral and northeast-trending left-lateral faults. Folds are broad and relatively minor. The major east-west-trending fault pattern may have been initially produced by extensional stresses related to subsidence of the "Tillamook island". The conjugate strike-slip fault pattern may have been created by partial coupling of the forearc basin with oblique subduction of the Farallon plate. Other than timber, locally used rock aggregate from small quarries is the only resource that has been realized in the thesis area. Most quarries are developed in dikes and sills of Grande Ronde Basalt and the aggregate is used to macadamize logging roads. Diagenetic events have resulted in significant loss of porosity and permeability of potential reservoir sandstones in the area. The most favorable targets are relatively matrix-free micaceous arkosic sandstones in the Sunset Highway member, but these have been breached by erosion in the eastern part of the thesis area and pinch out in the western part of the area where potential mudstone cap rocks (e.g., Hamlet and Keasey formations) are present. Mudstones in the area contain woody-structured kerogen and average about 1% total organic carbon. These potential source rocks are generally thermally immature but have locally been baked by basaltic intrusions. This results in elevated vitrinite reflectance values (in the oil window and beyond) and, therefore, the mudstones may be potential source rocks for methane generation. Mineralized fault zones have substantial width and length but do not appear to carry anomalous concentrations of any metals other than arsenic. High-grade supergene copper-silver mineralization associated with Cole Mountain basalt intrusions has been documented but appears to be very localized and is not thought to be a viable exploration target. Title: Geology of the Elsie-lower Nehalem River area, south-central Clatsop and northern Tillamook counties, northwestern Oregon Author: Mumford, Daniel Franklin The middle Eocene Tillamook Volcanics form the oldest rock unit in the Elsie-lower Nehalem River area. K-Ar age determinations and age constraints imposed by foraminiferal and calcareous nannofossil assemblages of overlying sedimentary strata indicate an absolute age of about 42 Ma for the uppermost Tillamook Volcanics. Major oxide values indicate that the upper Tillamook Volcanics are highly fractionated high Fe-Ti tholeiitic basalts and basaltic andesites. These volcanics were erupted in a developing forearc under an extensional plate tectonic setting and formed a moderately large oceanic island. These subaerial flows are predominantly aphyric to plagioclase-augite porphyritic and have a pilotaxitic flow texture. Epochs of both normal and reverse magnetic polarity are recorded. Thermal subsidence related to the end of the volcanism resulted in deposition of the transgressive late Eocene Hamlet formation over the "Tillamook island". The informal Hamlet formation consists of three members. From oldest to youngest they are: the Roy Creek member, the Sunset Highway member, and the Sweet Home Creek member. Three lithofacies are present in the Roy Creek member. The stratigraphically lowest of these consists of basaltic boulder-pebble conglomerate and locally fossiliferous pebbly basaltic sandstones which were deposited in a high energy nearshore environment around rocky basaltic headlands and sea stacks of the Tillamook Volcanics. Molluscan fossils in this lithofacies are correlative to the middle to late Eocene "CowlitzCoaledo" fauna. Successively overlying lithofacies are a very coarseto coarse-grained shallow marine basaltic sandstone lithofacies and a medium- to fine-grained basaltic sandstone lithofacies. This fining upward sequenced documents progressive deepening of the depositional basin. Framework clasts in all three Roy Creek member lithofacies were predominantly derived from the Tillamook Volcanics. Pore-filling diagenetic chlorite, smectite (nontronite), calcite, and zeolite (clinoptilolite and heulandite) cements severely reduce the porosity of Roy Creek member sandstones. The Sunset Highway member of the Hamlet formation conformably overlies the Roy Creek member in eastern Clatsop and western Columbia counties and pinches out to the west at about the longitude of the Nehalem River in T. 4 N., R. 8 W.. The Sunset Highway member is predominantly composed of interbedded micaceous arkosic sandstone, lithic arkose, and muddy micaceous arkosic siltstone with a few beds of basaltic sandstone and basaltic debris flow breccias. The dominant micaceous arkosic composition of the Sunset Highway member reflects a distant extrabasinal granitic-metamorphic provenance and contrasts with that of the locally derived underlying basaltic Roy Creek member. Low angle trough cross-bedding, hummocky bedding, and microcross-laminations in fine to medium-grained arkosic sandstones are interpreted to have been produced by large storm-generated waves and on a high energy inner shelf. Thin interbeds of bioturbated mudstone and mollusc-bearing bioturbated sandstones formed during periods of fairweather conditions and during lower sedimentation rates. Rare matrix supported, basaltic debris-flow breccias and basaltic sandstones were derived from nearby basaltic headlands and by rivers draining the Tillamook Volcanics. Minor secondary intraparticle porosity occurs with some primary intergranular porosity in relatively matrix-free Sunset Highway member arkosic sandstones. However, much of the porosity and permeability of these potential sandstones has been reduced by diagenetic smectite coatings on framework grains and potassium feldspar overgrowths of feldspars. The mudstone-dominated Sweet Home Creek member was conformably deposited on the Sunset Highway member in eastern Clatsop and western Columbia counties. In western Clatsop County the Sweet Home Creek member directly and conformably overlies the Roy Creek member due to pinch out of the Sunset Highway member. Upper Narizian to lowermost Refugian benthic foraminiferal assemblages from this unit indicate outer shelf to upper slope sedimentation and continued subsidence of the depositional (Astoria) basin. Micromicaceous and carbonaceous silty mudatone dominates this unit but thin-bedded micaceous arkosic turbidite sandstones are present in the lower part, and rare, thin basaltic turbidites are present in the upper half. X-ray diffraction analysis shows that the dominant clay minerals in the Sweet Home Creek member niudstone are smectite (montmorillonite), kaolinite, and illite. The Cole Mountain basalt (informal) intrudes and locally overlies the Sweet Home Creek member. This caic-alkaline basaltic andesite is thought to have formed in a compressional plate tectonic regime and been emplaced on the outer shelf and upper slope as shallow irregular sills and dikes and minor submarine pillow basalt-hyaloclastite complexes. Siliceous nodules associated with pillowed units locally contains a few per cent pyrite and are associated with small areas of high-grade supergene copper-silver mineralization. The normally polarized Cole Mountain basalt is chemically, petrographically, and lithologically distinct from the Tillamook Volcanics and Grande Ronde Basalt of the Columbia River Basalt Group. The uppermost Narizian and Refugian (late Eocene) Jewell member of the Keasey Formation disconformably overlies the Cole Mountain basalt and Sweet Home Creek member. A thin basal glauconitic sandstone-siltstone reflects a period of reduced sedimentation under slightly reducing conditions and marks the disconformity. The unit primarily consists of laminated to thin bedded tuffaceous mudstone with a few thin tuff beds, small micaceous arkosic sandstone channels and clastic dikes. Clay minerals in the Jewell member are dominated by smectite (montmorillonite), with minor kaolinite and illite (degraded mica) in the lower part of the unit. Benthic foraminiferal assemblages in the unit indicate bathyal or slope depths and have been assigned to the lower Refugian to upper Narizian stages. In the middle Miocene, irregular dikes and sills of the Grande Ronde Basalt of the Columbia River Basalt Group intruded the late Eocene sedimentary strata in the thesis area. Two magneto-chemical types of Grande Ronde Basalt, N2/low MgO-low Ti02 and N2/ high MgO, were identified in the thesis area. These were geochemically and magnetically correlated to subaerial flows of magneto-chemical types IA and 5A of Mangan and others (1986) on the Columbia Plateau. The intrusions or invasive flows are interpreted to have been derived from voluminous plateau eruptions by invasion into soft, unconsolidated Neogene sediments at the marine/coast interface and then into the more brittle but ductile Paleogene strata of the area as first proposed by Beeson and others (1979). Uplift of the Coast Range was initiated in the late Miocene as a result of rapid offshore underthrusting in the subduction zone (Snavely and others, 1983). This has resulted in subaerial erosion and exposure of the faulted and gently folded forearc ridge and deposition of Quaternary alluvial gravels and sands along major rivers and creek in the thesis area. The dominant structural features of the Elsie-lower Nehalem River area are generally down-to-the-north, east-west-trending high angle faults with oblique offset and a conjugate set of oblique slip northwest-trending right-lateral and northeast-trending left-lateral faults. Folds are broad and relatively minor. The major east-west-trending fault pattern may have been initially produced by extensional stresses related to subsidence of the "Tillamook island". The conjugate strike-slip fault pattern may have been created by partial coupling of the forearc basin with oblique subduction of the Farallon plate. Other than timber, locally used rock aggregate from small quarries is the only resource that has been realized in the thesis area. Most quarries are developed in dikes and sills of Grande Ronde Basalt and the aggregate is used to macadamize logging roads. Diagenetic events have resulted in significant loss of porosity and permeability of potential reservoir sandstones in the area. The most favorable targets are relatively matrix-free micaceous arkosic sandstones in the Sunset Highway member, but these have been breached by erosion in the eastern part of the thesis area and pinch out in the western part of the area where potential mudstone cap rocks (e.g., Hamlet and Keasey formations) are present. Mudstones in the area contain woody-structured kerogen and average about 1% total organic carbon. These potential source rocks are generally thermally immature but have locally been baked by basaltic intrusions. This results in elevated vitrinite reflectance values (in the oil window and beyond) and, therefore, the mudstones may be potential source rocks for methane generation. Mineralized fault zones have substantial width and length but do not appear to carry anomalous concentrations of any metals other than arsenic. High-grade supergene copper-silver mineralization associated with Cole Mountain basalt intrusions has been documented but appears to be very localized and is not thought to be a viable exploration target. Close

• 40. [Article] Geology of the Buster Creek-Nehalem Valley area, Clatsop County, northwest Oregon

  Six Tertiary rock units are exposed in the Buster Creek-Nehalem Valley area. They are, from oldest to youngest: upper Eocene Tillamook Volcanics; upper Eocene Cowlitz Formation; upper Eocene Keasey Formation; ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Buster Creek-Nehalem Valley area, Clatsop County, northwest Oregon Author: Olbinski, James Steven Six Tertiary rock units are exposed in the Buster Creek-Nehalem Valley area. They are, from oldest to youngest: upper Eocene Tillamook Volcanics; upper Eocene Cowlitz Formation; upper Eocene Keasey Formation; upper Eocene Vesper Church formation (informal); upper Eocene to Oligocene Pittsburg Bluff Formation; and middle Miocene Depoe Bay Basalt. The Tillamook Volcanics is composed of basaltic andesite subaerial flows (SiO2 54.19% to 55.67%) and volcanic debris flows. The platy jointed subaerial flows are generally porphyritic with a pilotaxitic groundmass; a few aphyric flows with well defined flow banding are present. Highly vesicular flow tops typically show alteration of ilmenite to leucoxene producing a diagnostic bleached white appearance. Debris flows are comprised of very poorly sorted, angular, volcanic and minor sedimentary rock clasts in a mud matrix. Commonly this lithology is intruded by porphyritic and vesicular dikes. Major oxides of the Tillamook basaltic andesites suggest that these volcanic rocks may have erupted in an oceanic island "spreading center" environment. The Cowlitz Formation unconformably overlies the Tillamook Volcanics in the study area. This formation is divided into five informal members: a basal basaltic andesite conglomerate; a unit of interbedded micaceous arkese, volcanic lithic arenite and mudstone; a thick structureless mudstone; rhythmically laminated turbidite sandstone and siltstone; and a thick upper arkosic sandstone. The basal conglomerate represents a fluvial braided stream to high energy marine shoreline environment. The finer grained middle members indicate a deepening up sequence. The upper sandstone member is a micaceous, well-sorted, hummocky bedded, porous, very friable sandstone deposited in a high energy storm-dominated shelf to nearshore environment. The upper sandstone member of the Cowlitz Formation ("Clark and Wilson sand" of the Mist gas field) is the current target of active drilling in adjacent areas by several petroleum companies. This upper sandstone and lower arkosic sandstones represent favorable targets in contact with organic-rich, but immature, source rocks in potential fault bounded structural highs and erosional pinchouts in the northern part of the study area. The Narizian to Refugian Keasey Formation is represented by the Jewell member (informal), in the study area. The Jewell member, a well-bedded to laminated, tuffaceous, indurated mudstone, unconformably overlies the more extensively faulted Cowlitz Formation. Upper slope water depths of 200-600 m are indicated by foraminiferal and molluscan assemblages. A lithologically distinct and mappable turbidite unit crops out in the study area and is informally named in this thesis the Vesper Church formation. The Vesper Church formation represents west- to northwest-trending turbidite-filled "sea gullies" deposited at bathyal depths (1,000-1,500 m) on the lower slope. Thin-bedded channelized turbidites with Bouma c, d and e sequences and local thick amalgamated sandstones characterize this unit. The upper Eocene (Refugian) Pittsburg Bluff Formation conformably overlies the Vesper Church formation. Molluscan assemblages from the basal part of this formation indicate water depths of 20-200 m; thus, a significant shallowing episode between the Vesper Church and Pittsburg Bluff formations is indicated. Thick, bioturbated, glauconitic to fine-grained tuffaceous sandstone and sandy mudstone suggest an inner to middle (possibly outer) continental shelf depositional environment for the Pittsburg Bluff strata. Following a period of high-angle northeast trending faulting, two middle Miocene Depoe Bay Basalt dikes intruded the sedimentary formations exposed in the area. The reversely polarized Northrup Creek dike can be traced over 8.5 km and has a paleomagnetic declination of 170° and a steep inclination of -74°, possibly a result of secular variation of the geomagnetic pole during cooling of the dike through its Cuire temperature (Nelson, 1983). These aphanitic to sparsely micro-porhyritic tholeiitic basalts are chemically identical to the Grande Ronde Basalt of the Columbia Plateau. A recent hypothesis by Beeson et al. (1979) suggests that all Miocene coastal basalts represent the distal ends of subaerial Columbia River basalts which reached the Miocene shoreline and intruded or "invaded" soft marine sediments. The reversed stratigraphic order of high and low MgO Depoe Bay (Grande Ronde) basaltic sills intruding Keasey and Cowlitz strata, as much as 1600 m below the surface in the petroleum exploration well Quintan_a Watzek 30-1 Watzek 30-1 in this study area, illustrates a complicating factor in the emplacement mechanism if these are "invasive" intrusions. In late middle Miocene the northern Oregon Coast Range anticline was formed, possibly in response to a period of underthrusting (Snavely et al., 1980b). Contemporaneously, a second set of left-lateral and right-lateral conjugate faults (N55°E and N55°W) cut the middle Miocene basalt dikes. This faulting may be related to north-south compression and clockwise rotation of western Oregon and southwest Washington associated with the oblique subduction of the Juan De Fuca Plate beneath the North American Plate as suggested by Magill et al. (1981) and Coe and Wells (1982). Title: Geology of the Buster Creek-Nehalem Valley area, Clatsop County, northwest Oregon Author: Olbinski, James Steven Six Tertiary rock units are exposed in the Buster Creek-Nehalem Valley area. They are, from oldest to youngest: upper Eocene Tillamook Volcanics; upper Eocene Cowlitz Formation; upper Eocene Keasey Formation; upper Eocene Vesper Church formation (informal); upper Eocene to Oligocene Pittsburg Bluff Formation; and middle Miocene Depoe Bay Basalt. The Tillamook Volcanics is composed of basaltic andesite subaerial flows (SiO2 54.19% to 55.67%) and volcanic debris flows. The platy jointed subaerial flows are generally porphyritic with a pilotaxitic groundmass; a few aphyric flows with well defined flow banding are present. Highly vesicular flow tops typically show alteration of ilmenite to leucoxene producing a diagnostic bleached white appearance. Debris flows are comprised of very poorly sorted, angular, volcanic and minor sedimentary rock clasts in a mud matrix. Commonly this lithology is intruded by porphyritic and vesicular dikes. Major oxides of the Tillamook basaltic andesites suggest that these volcanic rocks may have erupted in an oceanic island "spreading center" environment. The Cowlitz Formation unconformably overlies the Tillamook Volcanics in the study area. This formation is divided into five informal members: a basal basaltic andesite conglomerate; a unit of interbedded micaceous arkese, volcanic lithic arenite and mudstone; a thick structureless mudstone; rhythmically laminated turbidite sandstone and siltstone; and a thick upper arkosic sandstone. The basal conglomerate represents a fluvial braided stream to high energy marine shoreline environment. The finer grained middle members indicate a deepening up sequence. The upper sandstone member is a micaceous, well-sorted, hummocky bedded, porous, very friable sandstone deposited in a high energy storm-dominated shelf to nearshore environment. The upper sandstone member of the Cowlitz Formation ("Clark and Wilson sand" of the Mist gas field) is the current target of active drilling in adjacent areas by several petroleum companies. This upper sandstone and lower arkosic sandstones represent favorable targets in contact with organic-rich, but immature, source rocks in potential fault bounded structural highs and erosional pinchouts in the northern part of the study area. The Narizian to Refugian Keasey Formation is represented by the Jewell member (informal), in the study area. The Jewell member, a well-bedded to laminated, tuffaceous, indurated mudstone, unconformably overlies the more extensively faulted Cowlitz Formation. Upper slope water depths of 200-600 m are indicated by foraminiferal and molluscan assemblages. A lithologically distinct and mappable turbidite unit crops out in the study area and is informally named in this thesis the Vesper Church formation. The Vesper Church formation represents west- to northwest-trending turbidite-filled "sea gullies" deposited at bathyal depths (1,000-1,500 m) on the lower slope. Thin-bedded channelized turbidites with Bouma c, d and e sequences and local thick amalgamated sandstones characterize this unit. The upper Eocene (Refugian) Pittsburg Bluff Formation conformably overlies the Vesper Church formation. Molluscan assemblages from the basal part of this formation indicate water depths of 20-200 m; thus, a significant shallowing episode between the Vesper Church and Pittsburg Bluff formations is indicated. Thick, bioturbated, glauconitic to fine-grained tuffaceous sandstone and sandy mudstone suggest an inner to middle (possibly outer) continental shelf depositional environment for the Pittsburg Bluff strata. Following a period of high-angle northeast trending faulting, two middle Miocene Depoe Bay Basalt dikes intruded the sedimentary formations exposed in the area. The reversely polarized Northrup Creek dike can be traced over 8.5 km and has a paleomagnetic declination of 170° and a steep inclination of -74°, possibly a result of secular variation of the geomagnetic pole during cooling of the dike through its Cuire temperature (Nelson, 1983). These aphanitic to sparsely micro-porhyritic tholeiitic basalts are chemically identical to the Grande Ronde Basalt of the Columbia Plateau. A recent hypothesis by Beeson et al. (1979) suggests that all Miocene coastal basalts represent the distal ends of subaerial Columbia River basalts which reached the Miocene shoreline and intruded or "invaded" soft marine sediments. The reversed stratigraphic order of high and low MgO Depoe Bay (Grande Ronde) basaltic sills intruding Keasey and Cowlitz strata, as much as 1600 m below the surface in the petroleum exploration well Quintan_a Watzek 30-1 Watzek 30-1 in this study area, illustrates a complicating factor in the emplacement mechanism if these are "invasive" intrusions. In late middle Miocene the northern Oregon Coast Range anticline was formed, possibly in response to a period of underthrusting (Snavely et al., 1980b). Contemporaneously, a second set of left-lateral and right-lateral conjugate faults (N55°E and N55°W) cut the middle Miocene basalt dikes. This faulting may be related to north-south compression and clockwise rotation of western Oregon and southwest Washington associated with the oblique subduction of the Juan De Fuca Plate beneath the North American Plate as suggested by Magill et al. (1981) and Coe and Wells (1982). Close

• 41. [Article] The oligocene and miocene geology of the Tillamook embayment Tillamook County, northwest Oregon

  Eleven sedimentary and volcanic rock units are mapped and described in the thesis area, and chronicle the dynamic geologic history of the Tillamook embayment from the Oligocene through the middle Mlocene. ...

  Citation × Citation Citation Abstract Copy Title: The oligocene and miocene geology of the Tillamook embayment Tillamook County, northwest Oregon Author: Parker, Michael J. (Michael John), 1958- Eleven sedimentary and volcanic rock units are mapped and described in the thesis area, and chronicle the dynamic geologic history of the Tillamook embayment from the Oligocene through the middle Mlocene. The oldest unit is the Zemorrian to early Saucesian Smuggler Cove formation, a bathyal tuffaceous mudstone with some thin- to thick-bedded tuff layers deposited on the middle to upper continental slope during a period of explosive silicic volcanism in the Western Cascade arc. Uppermost Smuggler Cove strata are coarser grained, grading upward to arkosic turbidite sandstone and mudstone and thick bloturbated silty sandstone deposited on the outer shelf during marine regression. This regression heralded the progradation of the overlying shallow-marine Bewley Creek formation (informal) depositional system. The Bewley Creek formation (informal) is proposed in this study for a sequence of pumiceous, volcaniclastic-rich lower Miocene feldspathic litharenites and lithic arkoses deposited during the Pillarlan-stage near the mouth of an ancestral Columbia River. The unit grades from bioturbated silty sandstone to fine-grained hummocky cross-stratified and coarser grained channelized sandstones deposited within, or peripheral to a wave-dominated delta or ebb tidal-delta channel complex. Progradatlon of the Bewley Creek formation may have been caused, in part, by increased volcaniclastic sedimentation attending a pulse of explosive volcanism in the adjacent Western Cascade arc. Reduced volcanic activity, possibly coupled with basin subsidence or eustatic sea level rise, resulted in deposition of mudstones of the Sutton Creek member (informal; proposed) of the Nye Mudstone. The Saucesian Sutton Creek member consists of bathyal, laminated, carbonaceous, and moderately tuffaceous mudstone deposited in an upper continental slope basin. The upper part of the unit contains common lithic to arkosic turbidite sandstone interbeds within nested channel-fill deposits. These strata represent a channelized shelf-slope break environment adjacent to the shallow-marine Angora Peak member of the Astoria Formation depositlonal system. Subsequent marine regression resulted in progradation of the Pillarian- to Newportian-stage arkosic-micaceous sandstone-rich Angora Peak member into the Tillamook embayment. Grainsize analysis, sandstone petrography, scanning electron microscopy, and heavy mineral analyses suggest these lower to middle Miocene mollusk-bearing, fine- to medium-grained sandstones were predominantly deposited near the mouth of an ancestral Columbia River. They accumulated on a high-energy Inner shelf within or down drift of a wave-dominated delta or ebb-tidal delta complex, evidenced by paleocurrent analyses, hummocky cross-stratification and trough cross-stratified submarine channel-fill sequences. The Angora Peak member disconformably overlies Zemorrian mudstones of the Smuggler Cove formation at Cape Kiwanda suggesting local uplift and erosion in that area, followed by Newportian stage transgression in the Tillamook embayment. Exotic cobbles and boulders of two mica granite and sedimentary quartzite at Cape Kiwanda were probably derived from the Idaho Batholith and Precambrian sandstone terrains in Montana, transported via an ancestral Columbia River and longshore current to the shelf possibly bound within tree root bundles. The Netarts Bay member (informal) of the Astoria Formation Is proposed In this study for a late Sauceslan package of fine-grained to pebbly amalgamated and interbedded turbidite, grainflow, and fluldized flow friable thick-bedded lithic arkoses. These massive sandstones contain large penecontemporaneously emplaced channel wall-blocks and naller slltstone rip-ups. These lower to middle Miocene strata were deposited in a submarine canyon head and channel complex offshore of the shallow-marine Angora Peak member depositlonal system. Netarts Bay strata cut Into the underlying Angora Peak shelf strata, and cut and Interfinger with bathyal slope mudstones of the Cannon Beach member of the Astoria Formation. The overlying lower Cannon Beach member Is composed of laminated bathyal mudstones with rare turbidite sandstone interbeds deposited in a coarse clastic-starved slope environment. Upper Cannon Beach member strata In the Tillamook area are characterized by micaceous arkosic and lithic arkosic turbidite sandstones that underlie and occur within nested channel-fill sequences. Bloturbated carbonaceous cross-bedded sandstone In the upper Cannon Beach member records shallowing of the Tillamook embayment to a channelized upper slope to shelf environment. The Tillamook embayment was uplifted and dissected prior to the arrival of six to ten Intracanyon subaerial and submarine lava flows of the Columbia River Basalt Group. These middle Miocene flows, delineatedon the basis of geochemical composition and magnetic polarity, Include (in stratigraphic order) the Grouse Creek (R2 low MgO-low T102), Winterwater (N2 low MgO-low Ti02), and Sentinel Bluffs (high MgO) units of the Grande Ronde Basalt, and the Ginkgo unit of the Frenchman Springs member of the Wanapum Basalt. Orientation of Grande Ponde Basalt foreset-bedded pillow palagonite complexes and lava delta sequences indicate that these Columbia River Basalt units flowed westward into the Tillainook embayment, possibly through a saddle in the ancestral Oregon Coast Range. Marine transgression and deposition of hummocky cross-stratified arkosic marine strata of the Sandstone of Whale Cove followed emplacement of the last Grande Ronde flows. This was succeeded by a regression, as Indicated by the overlying subaerial plagioclase-phyric Ginkgo Unit flow of the Frenchman Springs Basalt. Locally, Winterwater and Sentinel Bluffs unit basalt occur as brecciated peperitic sills and dikes. These were emplaced through the process of "auto-invasion" when dense lava injected downward Into semi-lithifled Tertiary strata under the influence of both a pressure head augmented by flashing steam, and steam blasting. The thesis area is crossed by a complex network of high-angle northwest- and northeast-tending normal and reverse faults, and both low and high-angle east-trending reverse and thrust faults. These faults may have developed through a north-south compressional tectonic regime, a dextral shear couple, or a combination of these two tectonic regimes. Many faults cut Columbia River Basalt units and are thus middle Miocene or younger in age. Tertiary strata including the Columbia River Basalts are also folded within a broad westward-plunging syncline which suggests a middle Miocene or younger compressional event. Source rock analyses indicate that the mudstones of the Cannon Beach member, Sutton Creek member, and Smuggler Cove formation contain type III kerogen capable of generating natural gas only. Although these rocks have thermally innature vitrinite reflectance values, they contain sufficiently high total organic carbon content to be considered potential lean source rocks. Arkosic sandstones of the Angora Peak and Netarts Bay members have fair to good reservoir rock characteristics, and may represent reservoirs offshore for matured hydrocarbons generated from deeply buried source rocks. Title: The oligocene and miocene geology of the Tillamook embayment Tillamook County, northwest Oregon Author: Parker, Michael J. (Michael John), 1958- Eleven sedimentary and volcanic rock units are mapped and described in the thesis area, and chronicle the dynamic geologic history of the Tillamook embayment from the Oligocene through the middle Mlocene. The oldest unit is the Zemorrian to early Saucesian Smuggler Cove formation, a bathyal tuffaceous mudstone with some thin- to thick-bedded tuff layers deposited on the middle to upper continental slope during a period of explosive silicic volcanism in the Western Cascade arc. Uppermost Smuggler Cove strata are coarser grained, grading upward to arkosic turbidite sandstone and mudstone and thick bloturbated silty sandstone deposited on the outer shelf during marine regression. This regression heralded the progradation of the overlying shallow-marine Bewley Creek formation (informal) depositional system. The Bewley Creek formation (informal) is proposed in this study for a sequence of pumiceous, volcaniclastic-rich lower Miocene feldspathic litharenites and lithic arkoses deposited during the Pillarlan-stage near the mouth of an ancestral Columbia River. The unit grades from bioturbated silty sandstone to fine-grained hummocky cross-stratified and coarser grained channelized sandstones deposited within, or peripheral to a wave-dominated delta or ebb tidal-delta channel complex. Progradatlon of the Bewley Creek formation may have been caused, in part, by increased volcaniclastic sedimentation attending a pulse of explosive volcanism in the adjacent Western Cascade arc. Reduced volcanic activity, possibly coupled with basin subsidence or eustatic sea level rise, resulted in deposition of mudstones of the Sutton Creek member (informal; proposed) of the Nye Mudstone. The Saucesian Sutton Creek member consists of bathyal, laminated, carbonaceous, and moderately tuffaceous mudstone deposited in an upper continental slope basin. The upper part of the unit contains common lithic to arkosic turbidite sandstone interbeds within nested channel-fill deposits. These strata represent a channelized shelf-slope break environment adjacent to the shallow-marine Angora Peak member of the Astoria Formation depositlonal system. Subsequent marine regression resulted in progradation of the Pillarian- to Newportian-stage arkosic-micaceous sandstone-rich Angora Peak member into the Tillamook embayment. Grainsize analysis, sandstone petrography, scanning electron microscopy, and heavy mineral analyses suggest these lower to middle Miocene mollusk-bearing, fine- to medium-grained sandstones were predominantly deposited near the mouth of an ancestral Columbia River. They accumulated on a high-energy Inner shelf within or down drift of a wave-dominated delta or ebb-tidal delta complex, evidenced by paleocurrent analyses, hummocky cross-stratification and trough cross-stratified submarine channel-fill sequences. The Angora Peak member disconformably overlies Zemorrian mudstones of the Smuggler Cove formation at Cape Kiwanda suggesting local uplift and erosion in that area, followed by Newportian stage transgression in the Tillamook embayment. Exotic cobbles and boulders of two mica granite and sedimentary quartzite at Cape Kiwanda were probably derived from the Idaho Batholith and Precambrian sandstone terrains in Montana, transported via an ancestral Columbia River and longshore current to the shelf possibly bound within tree root bundles. The Netarts Bay member (informal) of the Astoria Formation Is proposed In this study for a late Sauceslan package of fine-grained to pebbly amalgamated and interbedded turbidite, grainflow, and fluldized flow friable thick-bedded lithic arkoses. These massive sandstones contain large penecontemporaneously emplaced channel wall-blocks and naller slltstone rip-ups. These lower to middle Miocene strata were deposited in a submarine canyon head and channel complex offshore of the shallow-marine Angora Peak member depositlonal system. Netarts Bay strata cut Into the underlying Angora Peak shelf strata, and cut and Interfinger with bathyal slope mudstones of the Cannon Beach member of the Astoria Formation. The overlying lower Cannon Beach member Is composed of laminated bathyal mudstones with rare turbidite sandstone interbeds deposited in a coarse clastic-starved slope environment. Upper Cannon Beach member strata In the Tillamook area are characterized by micaceous arkosic and lithic arkosic turbidite sandstones that underlie and occur within nested channel-fill sequences. Bloturbated carbonaceous cross-bedded sandstone In the upper Cannon Beach member records shallowing of the Tillamook embayment to a channelized upper slope to shelf environment. The Tillamook embayment was uplifted and dissected prior to the arrival of six to ten Intracanyon subaerial and submarine lava flows of the Columbia River Basalt Group. These middle Miocene flows, delineatedon the basis of geochemical composition and magnetic polarity, Include (in stratigraphic order) the Grouse Creek (R2 low MgO-low T102), Winterwater (N2 low MgO-low Ti02), and Sentinel Bluffs (high MgO) units of the Grande Ronde Basalt, and the Ginkgo unit of the Frenchman Springs member of the Wanapum Basalt. Orientation of Grande Ponde Basalt foreset-bedded pillow palagonite complexes and lava delta sequences indicate that these Columbia River Basalt units flowed westward into the Tillainook embayment, possibly through a saddle in the ancestral Oregon Coast Range. Marine transgression and deposition of hummocky cross-stratified arkosic marine strata of the Sandstone of Whale Cove followed emplacement of the last Grande Ronde flows. This was succeeded by a regression, as Indicated by the overlying subaerial plagioclase-phyric Ginkgo Unit flow of the Frenchman Springs Basalt. Locally, Winterwater and Sentinel Bluffs unit basalt occur as brecciated peperitic sills and dikes. These were emplaced through the process of "auto-invasion" when dense lava injected downward Into semi-lithifled Tertiary strata under the influence of both a pressure head augmented by flashing steam, and steam blasting. The thesis area is crossed by a complex network of high-angle northwest- and northeast-tending normal and reverse faults, and both low and high-angle east-trending reverse and thrust faults. These faults may have developed through a north-south compressional tectonic regime, a dextral shear couple, or a combination of these two tectonic regimes. Many faults cut Columbia River Basalt units and are thus middle Miocene or younger in age. Tertiary strata including the Columbia River Basalts are also folded within a broad westward-plunging syncline which suggests a middle Miocene or younger compressional event. Source rock analyses indicate that the mudstones of the Cannon Beach member, Sutton Creek member, and Smuggler Cove formation contain type III kerogen capable of generating natural gas only. Although these rocks have thermally innature vitrinite reflectance values, they contain sufficiently high total organic carbon content to be considered potential lean source rocks. Arkosic sandstones of the Angora Peak and Netarts Bay members have fair to good reservoir rock characteristics, and may represent reservoirs offshore for matured hydrocarbons generated from deeply buried source rocks. Close

• 42. [Article] Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Centre, Kermadec Arc

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. ...

  Citation × Citation Citation Abstract Copy Title: Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Centre, Kermadec Arc Author: Schwarz-Schampera, Ulrich, Lupton, John, Baker, Edward T., Butterfield, David A., Hannington, Mark D., Leybourne, Matthew I., Chadwick, William W., Jr., Faure, Kevin, Embley, Robert W., Walker, Sharon L., Clark, Malcolm, Timm, Christian, Wright, Ian C., Massoth, Gary J., Resing, Joe, de Ronde, Cornel E. J., Graham, Ian J. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Society of Economic Geologists and can be found at: http://econgeol.geoscienceworld.org/. Title: Submarine Magmatic-Hydrothermal Systems at the Monowai Volcanic Centre, Kermadec Arc Author: Schwarz-Schampera, Ulrich, Lupton, John, Baker, Edward T., Butterfield, David A., Hannington, Mark D., Leybourne, Matthew I., Chadwick, William W., Jr., Faure, Kevin, Embley, Robert W., Walker, Sharon L., Clark, Malcolm, Timm, Christian, Wright, Ian C., Massoth, Gary J., Resing, Joe, de Ronde, Cornel E. J., Graham, Ian J. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Society of Economic Geologists and can be found at: http://econgeol.geoscienceworld.org/. Close

• 43. [Article] Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon

  The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks ...

  Citation × Citation Citation Abstract Copy Title: Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon Author: Rarey, Phillip Jay The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks were produced in an extensional tectonic setting in the developing forearc and formed an extensive tholeiltic oceanic island. The volcanics consi5t of a thick sequence of normally and reversely polarized subaerial basalt and basaltic andesite flows in the Hamlet-North Fork of the Nehalem River area. The "Gray's River area" Goble Volcanics in southwest Washington are chemically and stratigraphically correlative to the Tillamook Volcanics. Cessation of Tillamook volcanism resulted in thermal subsidence and transgression of the overlying Hamlet formation. Upper Narizian (middle to upper Eccene) nearshore fossiliferous basaltic boulder-pebble conglomerates and basaltic sandstones of the Roy Creek member of the Hamlet formation (informal) were deposited along a rocky basaltic coastline over the subsiding volcanic "island". Scanning electron microscopy shows that radial pore-filling chloritic cement has significantly reduced porosity in Roy Creek member sandstones. Micaceous and carbonaceous silty mudstones and rare thin basaltic turbidite sandstones of the Sweet Home Creek member of the Hamlet formation (informal> were deposited on the outer shelf to upper slope above the Roy Creek member as the basin continued to deepen. The Sweet Home Creek member contains abundant bathyal benthtc foraminifera assignable to the upper Narizian stage. Calcareous nannofossils collected from the unit have been assigned to subzone CP-14a which is in agreement with foraminifera data. The upper part of the Sweet Home Creek member is in part a deep marine correlative to shelf arkosic sandstones of the Cowltiz Formation which pinches out into the Sweet Home Creek member in eastern Clatsop County. Much of the detritus in the Sweet Home Creek member was derived from plutonic and metamorphic sources in contrast to the locally derived Roy Creek member. Calc-alkaline Cole Mountain basalt (informal) intrudes and overlies the Sweet Home Creek member. Cole Mountain basalt was formed in a compressional tectonic environment and emplaced on the outer continental shelf as shallow intrusions and submarine flow. The unit is chemically and petrographically distinct from the Tillamook Volcanics and chemically similar to and stratigraphically correlative to the type Goble Volcanics (e.g. low Ti02 and low P205). Unconformably overlying the Cole Mountain basalt and the Sweet Home Creek member is the bathyal, Refugian (upper Eocene), Jewell member of the Keasey Formation. It consists of three parts a basal glauconitic sandstone-siltstone, a laminated tuffaceous sandstone unit with rare small arkosic sandstone channels and occasional clastic dikes, and an upper laminated to bioturbated tuffaceous silt-mudstone. trkosic sandstones were derived from an ancesteral Columbia River system whereas abundant tuffaceous detritus was derived locally from the Cascade arc. The Refugian lower Smuggler Cove formation (informal) gradationally overlies the Jewell member and consists of bioturbated, tuffaceous, bathyal mudstones. Outer shelf, very fine-grained tuffaceous sandstones of the David Douglas tongue (informal) of the Pittsburg Bluff Formation and deeper marine correlative outer shelf to upper slope glauconitic sanstones of the middle Smuggler Cove formation overlie the lower Smuggler Cove formation. The upper Smuggler Cove formation consists of uppermost Refugian to Zemmorian bathyal, bioturbated, fossiliferous, well-indurated tuffaceous siltstone. Laminated carbonaceous mudetones and thin (<1/2 m) arkosic sandstone beds of the ball park unit in the Smuggler Cove formation overlie and interfinger with (7) the upper Smuggler Cove formation. The ball park unit is late Zemorrian (Oligocene) or Saucesian (Early Miocene) in age. Fluvial-deltaic to shallow marine sandstones and conglomerates of the lower to middle Miocene angora Peek member of the astoria Formation unconformably overlies the Smuggler Cove formation. Numerous middle to upper Miocene basalts and gabbros intrude the sedimentary rocks in the thesis area. The intrusive rocks are chemically, magnetically, petrographically, and chronologically correlative to the Grande Ronde Basalt, Frenchman Springs Member, and Pomona Member of the Columbia River Basalt Group on the Columbia Plateau. The Grande Ronde Basalt intrusives have been divided into three chemical-magnetostratigraphic units in the thesis area and correlated to subaerial Columbia River Basalt flows located approximately 35 km to the northeast. The intrusive rocks are thought to have formed by invasion of voluminous subaerial flows into soft, semiconsolidated marine sediments as first envisioned by Beeson et. al. (1979). Uplift of the Coast Range forearc ridge from late Miocene to present has resulted in subaerial erosion and exposure of rock units. Thin alluvial gravels and sands were deposited in the southeastern corner of the thesis area during the Quaternary. Structure in the thesis area is dominated by a series of east-west trending high angle faults and a younger series of conjugate northeast-and northwest-trending high angle oblique slip faults. Proton precession magnetometer traverses confirm the presence of the faults. The structure may have been produced by partial coupling of the forearc region with the subducting Farallon plate. The thesis area has been actively explored for hydrocarbons. Geologic mapping, however, shows that significant sandstone reservoirs are not present in the subsurface and, therefore, the area has low potential of hydrocarbon production. Mudstones in the thesis area average approximately 0.9-1.1% total organic carbon with vitrinite reflectance values ranging from 0.53% Ro (unbaked) to 0.72% Ro (baked). Therefore, the mudstones are a marginal to poor source of thermogenic gas but a possible source of methane gas. Title: Geology of the Hamlet-North Fork of the Nehalem River area, southern Clatsop and northernmost Tillamook Counties, northwest Oregon Author: Rarey, Phillip Jay The middle to late Eocene tholeiitic Tillamook Volcanics compose the oldest rock unit in the Hamlet-North Fork of the Nehalem River area. Geochemical plots and field relationships indicate that these rocks were produced in an extensional tectonic setting in the developing forearc and formed an extensive tholeiltic oceanic island. The volcanics consi5t of a thick sequence of normally and reversely polarized subaerial basalt and basaltic andesite flows in the Hamlet-North Fork of the Nehalem River area. The "Gray's River area" Goble Volcanics in southwest Washington are chemically and stratigraphically correlative to the Tillamook Volcanics. Cessation of Tillamook volcanism resulted in thermal subsidence and transgression of the overlying Hamlet formation. Upper Narizian (middle to upper Eccene) nearshore fossiliferous basaltic boulder-pebble conglomerates and basaltic sandstones of the Roy Creek member of the Hamlet formation (informal) were deposited along a rocky basaltic coastline over the subsiding volcanic "island". Scanning electron microscopy shows that radial pore-filling chloritic cement has significantly reduced porosity in Roy Creek member sandstones. Micaceous and carbonaceous silty mudstones and rare thin basaltic turbidite sandstones of the Sweet Home Creek member of the Hamlet formation (informal> were deposited on the outer shelf to upper slope above the Roy Creek member as the basin continued to deepen. The Sweet Home Creek member contains abundant bathyal benthtc foraminifera assignable to the upper Narizian stage. Calcareous nannofossils collected from the unit have been assigned to subzone CP-14a which is in agreement with foraminifera data. The upper part of the Sweet Home Creek member is in part a deep marine correlative to shelf arkosic sandstones of the Cowltiz Formation which pinches out into the Sweet Home Creek member in eastern Clatsop County. Much of the detritus in the Sweet Home Creek member was derived from plutonic and metamorphic sources in contrast to the locally derived Roy Creek member. Calc-alkaline Cole Mountain basalt (informal) intrudes and overlies the Sweet Home Creek member. Cole Mountain basalt was formed in a compressional tectonic environment and emplaced on the outer continental shelf as shallow intrusions and submarine flow. The unit is chemically and petrographically distinct from the Tillamook Volcanics and chemically similar to and stratigraphically correlative to the type Goble Volcanics (e.g. low Ti02 and low P205). Unconformably overlying the Cole Mountain basalt and the Sweet Home Creek member is the bathyal, Refugian (upper Eocene), Jewell member of the Keasey Formation. It consists of three parts a basal glauconitic sandstone-siltstone, a laminated tuffaceous sandstone unit with rare small arkosic sandstone channels and occasional clastic dikes, and an upper laminated to bioturbated tuffaceous silt-mudstone. trkosic sandstones were derived from an ancesteral Columbia River system whereas abundant tuffaceous detritus was derived locally from the Cascade arc. The Refugian lower Smuggler Cove formation (informal) gradationally overlies the Jewell member and consists of bioturbated, tuffaceous, bathyal mudstones. Outer shelf, very fine-grained tuffaceous sandstones of the David Douglas tongue (informal) of the Pittsburg Bluff Formation and deeper marine correlative outer shelf to upper slope glauconitic sanstones of the middle Smuggler Cove formation overlie the lower Smuggler Cove formation. The upper Smuggler Cove formation consists of uppermost Refugian to Zemmorian bathyal, bioturbated, fossiliferous, well-indurated tuffaceous siltstone. Laminated carbonaceous mudetones and thin (<1/2 m) arkosic sandstone beds of the ball park unit in the Smuggler Cove formation overlie and interfinger with (7) the upper Smuggler Cove formation. The ball park unit is late Zemorrian (Oligocene) or Saucesian (Early Miocene) in age. Fluvial-deltaic to shallow marine sandstones and conglomerates of the lower to middle Miocene angora Peek member of the astoria Formation unconformably overlies the Smuggler Cove formation. Numerous middle to upper Miocene basalts and gabbros intrude the sedimentary rocks in the thesis area. The intrusive rocks are chemically, magnetically, petrographically, and chronologically correlative to the Grande Ronde Basalt, Frenchman Springs Member, and Pomona Member of the Columbia River Basalt Group on the Columbia Plateau. The Grande Ronde Basalt intrusives have been divided into three chemical-magnetostratigraphic units in the thesis area and correlated to subaerial Columbia River Basalt flows located approximately 35 km to the northeast. The intrusive rocks are thought to have formed by invasion of voluminous subaerial flows into soft, semiconsolidated marine sediments as first envisioned by Beeson et. al. (1979). Uplift of the Coast Range forearc ridge from late Miocene to present has resulted in subaerial erosion and exposure of rock units. Thin alluvial gravels and sands were deposited in the southeastern corner of the thesis area during the Quaternary. Structure in the thesis area is dominated by a series of east-west trending high angle faults and a younger series of conjugate northeast-and northwest-trending high angle oblique slip faults. Proton precession magnetometer traverses confirm the presence of the faults. The structure may have been produced by partial coupling of the forearc region with the subducting Farallon plate. The thesis area has been actively explored for hydrocarbons. Geologic mapping, however, shows that significant sandstone reservoirs are not present in the subsurface and, therefore, the area has low potential of hydrocarbon production. Mudstones in the thesis area average approximately 0.9-1.1% total organic carbon with vitrinite reflectance values ranging from 0.53% Ro (unbaked) to 0.72% Ro (baked). Therefore, the mudstones are a marginal to poor source of thermogenic gas but a possible source of methane gas. Close

• 44. [Article] Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes

  Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their ...

  Citation × Citation Citation Abstract Copy Title: Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes Author: Tierney, Casey R. Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust. The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is characterized by episodic volcanism over a ~11 Ma time-span that climaxed about 4 Ma. Since peak activity, the temporal and spatial record of volcanism suggests a waning of the system with only one other supervolcanic eruption at 2.6 Ma. The most recent phase of volcanism from the APVC comprises a series of late Pleistocene domes that share a general petrochemical resemblance to the ignimbrites. New U-Th/U-Pb data on zircons and high precision 40Ar/39Ar age determinations reveal that these effusive eruptions represent a temporally coherent magmatic episode. The five largest domes (Chao, Chillahuita, Chanka, Chascon-Runtu Jarita, and Tocopuri) have a combined volume >40 km³, and are distributed over a roughly elliptical area of almost 2000km² centered at 22°S 68°W. They are crystal rich (>50%) dacites to rhyolites. ⁴⁰Ar/³⁹Ar ages from biotite reveals eruption ages from 108±6 to 120±5 ka while more accurate sanidine for some of the domes reveal eruption ages from 87±4 to 97±2 ka. SIMS U-series crystallization ages from the rims of 215 zircon crystals from the domes show a similar age spectra from dome to dome, with common peaks in zircon ages at ~100ka and ~220ka. Furthermore, the ages reveal a fairly continuous spread of ages from near eruption to >300ka indicating that the residence time of this magma body was likely over a similar time interval. Ubiquitous andesitic inclusions evidence a vital role for recharge in sustaining and maybe eventual eruption of these magmas. Lastly, the interiors of crystals with rim U-Th secular equilibrium ages were re-analyzed and have yielded U-Pb ages of up to 3.5 Ma. The presence of these older interiors suggests that the source region of these magmas retained a record of an earlier history dating back to the last supervolcanic eruption in the region from the nearby Pastos Grandes caldera. This suggests that the thermal history of the system precluded complete resorption of antecrysts. The volcanological, petrological, temporal and spatial coherence of this series of eruptions combined with the similar ⁴⁰Ar/³⁹Ar and zircon age spectra argue for a long-lived and unitary magma chamber revealing perhaps the waning of this major continental magma system. Title: Timescales of large silicic magma systems : implications from accessory minerals in Pleistocene lavas of the Altiplano-Puna Volcanic Complex, central Andes Author: Tierney, Casey R. Constraining the development, evolution, and timescales of large silicic magma systems is important to understanding the development of granite batholiths, the relationships between volcanoes and their plutonic underpinnings, and the development of the continental crust. The ignimbrite flare up that produced the Altiplano-Puna Volcanic Complex of the Central Andes is characterized by episodic volcanism over a ~11 Ma time-span that climaxed about 4 Ma. Since peak activity, the temporal and spatial record of volcanism suggests a waning of the system with only one other supervolcanic eruption at 2.6 Ma. The most recent phase of volcanism from the APVC comprises a series of late Pleistocene domes that share a general petrochemical resemblance to the ignimbrites. New U-Th/U-Pb data on zircons and high precision 40Ar/39Ar age determinations reveal that these effusive eruptions represent a temporally coherent magmatic episode. The five largest domes (Chao, Chillahuita, Chanka, Chascon-Runtu Jarita, and Tocopuri) have a combined volume >40 km³, and are distributed over a roughly elliptical area of almost 2000km² centered at 22°S 68°W. They are crystal rich (>50%) dacites to rhyolites. ⁴⁰Ar/³⁹Ar ages from biotite reveals eruption ages from 108±6 to 120±5 ka while more accurate sanidine for some of the domes reveal eruption ages from 87±4 to 97±2 ka. SIMS U-series crystallization ages from the rims of 215 zircon crystals from the domes show a similar age spectra from dome to dome, with common peaks in zircon ages at ~100ka and ~220ka. Furthermore, the ages reveal a fairly continuous spread of ages from near eruption to >300ka indicating that the residence time of this magma body was likely over a similar time interval. Ubiquitous andesitic inclusions evidence a vital role for recharge in sustaining and maybe eventual eruption of these magmas. Lastly, the interiors of crystals with rim U-Th secular equilibrium ages were re-analyzed and have yielded U-Pb ages of up to 3.5 Ma. The presence of these older interiors suggests that the source region of these magmas retained a record of an earlier history dating back to the last supervolcanic eruption in the region from the nearby Pastos Grandes caldera. This suggests that the thermal history of the system precluded complete resorption of antecrysts. The volcanological, petrological, temporal and spatial coherence of this series of eruptions combined with the similar ⁴⁰Ar/³⁹Ar and zircon age spectra argue for a long-lived and unitary magma chamber revealing perhaps the waning of this major continental magma system. Close

• 45. [Article] Partial melting of tonalite at the margins of a Columbia River Basalt Group dike, Wallowa Mountains, northeastern Oregon

  Columbia River Basalt Group dikes cut the tonalite-granodiorite Wallowa Batholith in northeastern Oregon, providing a natural setting in which to examine partial melting. Many dikes have up to 5 m-wide ...

  Citation × Citation Citation Abstract Copy Title: Partial melting of tonalite at the margins of a Columbia River Basalt Group dike, Wallowa Mountains, northeastern Oregon Author: Petcovic, Heather L. Columbia River Basalt Group dikes cut the tonalite-granodiorite Wallowa Batholith in northeastern Oregon, providing a natural setting in which to examine partial melting. Many dikes have up to 5 m-wide zones of quenched partially melted wallrock at their margins. This paper examines the progressive partial melting reactions in biotite-and hornblende-bearing tonalite at the margin of a near-vertical Grande Ronde dike in the vicinity of Maxwell Lake. Paleodepth at the time of dike emplacement is estimated at 1- 2 km, and dike temperature was about 1140°C. Samples collected from the dike margin represent five successive stages of melt reaction over a distance of about 5 m from unmolten wallrock (Stage 1) to about 40 volume percent (vol%) quenched melt (Stage 5). This melt is now represented by about 31 vol% silicic glass that has undergone little to no devitrification and about 9 vol% plagioclase, pyroxene, and Fe-Ti oxide quench crystals. Whole rock major and trace element bulk compositional data are nearly identical to unmolten rock at each stage, suggesting that the melt did not separate from the restite and each stage represents essentially a chemically closed system. With progressive melting, primary hornblende, biotite, and orthoclase are entirely consumed but residual plagioclase, quartz, Fe-Ti oxides and apatite persist in the restite. Hornblende dehydration initially produces a dusty intergrowth of augite, pigeonite, lesser enstatite, and sparse Fe-Ti oxides. Initial biotite dehydration produces titaniferous magnetite and lesser ilmenite aligned in bands in an intergrowth of enstatite and plagioclase. Andesine plagioclase develops a spongy texture as the albite component is lost to the melt. Reaction of hornblende, quartz, and feldspar produces sparse tonalitic (high-Ca) glass, while the reaction of biotite, quartz, and feldspar produces abundant granitic (high-K) glass. The two glass types are irregularly distributed around mafic reaction sites and in up to 2 mm seams on quartz-feldspar contacts. With progressive melting, replacement phases become compositionally more homogeneous, clinopyroxene is consumed, the proportion of plagioclase decreases, and glasses become slightly more mafic. Granitic and tonalitic glasses persist in just over 31 vol% glass suggesting that deformation is required to mix these melt types. Title: Partial melting of tonalite at the margins of a Columbia River Basalt Group dike, Wallowa Mountains, northeastern Oregon Author: Petcovic, Heather L. Columbia River Basalt Group dikes cut the tonalite-granodiorite Wallowa Batholith in northeastern Oregon, providing a natural setting in which to examine partial melting. Many dikes have up to 5 m-wide zones of quenched partially melted wallrock at their margins. This paper examines the progressive partial melting reactions in biotite-and hornblende-bearing tonalite at the margin of a near-vertical Grande Ronde dike in the vicinity of Maxwell Lake. Paleodepth at the time of dike emplacement is estimated at 1- 2 km, and dike temperature was about 1140°C. Samples collected from the dike margin represent five successive stages of melt reaction over a distance of about 5 m from unmolten wallrock (Stage 1) to about 40 volume percent (vol%) quenched melt (Stage 5). This melt is now represented by about 31 vol% silicic glass that has undergone little to no devitrification and about 9 vol% plagioclase, pyroxene, and Fe-Ti oxide quench crystals. Whole rock major and trace element bulk compositional data are nearly identical to unmolten rock at each stage, suggesting that the melt did not separate from the restite and each stage represents essentially a chemically closed system. With progressive melting, primary hornblende, biotite, and orthoclase are entirely consumed but residual plagioclase, quartz, Fe-Ti oxides and apatite persist in the restite. Hornblende dehydration initially produces a dusty intergrowth of augite, pigeonite, lesser enstatite, and sparse Fe-Ti oxides. Initial biotite dehydration produces titaniferous magnetite and lesser ilmenite aligned in bands in an intergrowth of enstatite and plagioclase. Andesine plagioclase develops a spongy texture as the albite component is lost to the melt. Reaction of hornblende, quartz, and feldspar produces sparse tonalitic (high-Ca) glass, while the reaction of biotite, quartz, and feldspar produces abundant granitic (high-K) glass. The two glass types are irregularly distributed around mafic reaction sites and in up to 2 mm seams on quartz-feldspar contacts. With progressive melting, replacement phases become compositionally more homogeneous, clinopyroxene is consumed, the proportion of plagioclase decreases, and glasses become slightly more mafic. Granitic and tonalitic glasses persist in just over 31 vol% glass suggesting that deformation is required to mix these melt types. Close

• 46. [Article] Sequence stratigraphy and lithofacies of the middle Eocene upper McIntosh and Cowlitz Formations, geology of the Grays River Volcanics, Castle Rock - Germany Creek area, southwest Washington

  A composite 732-rn thick section in Germany Creek of middle Eocene upper McIntosh and lower Cowlitz Formations, as well as the lower Grays River Volcanics, was studied using bio-, magneto- and lithostratigraphy ...

  Citation × Citation Citation Abstract Copy Title: Sequence stratigraphy and lithofacies of the middle Eocene upper McIntosh and Cowlitz Formations, geology of the Grays River Volcanics, Castle Rock - Germany Creek area, southwest Washington Author: Kleibacker, Derik W. A composite 732-rn thick section in Germany Creek of middle Eocene upper McIntosh and lower Cowlitz Formations, as well as the lower Grays River Volcanics, was studied using bio-, magneto- and lithostratigraphy to construct a sequence stratigraphic framework and assess hydrocarbon exploration potential. The upper McIntosh Formation forms a complete 3rd order depositional cycle that includes shallow marine, tide- and wave-dominated sandstones (upper McIntosh sandstone member) and overlying bathyal to outer-shelf siltstone (upper Mcintosh siltsone member). The upper McIntosh Formation coffelates to Chrons C19r (41.5 -42.5 Ma) and lower Chron 19n (41.5-41.2 Ma). A 31 order sequence boundary straddling Chron 19n (41.2-41.5 Ma) shows truncation of the highstand upper McIntosh siltstone by prograding lowstand shoreface parasequences of the lower Cowlitz Formation. The overlying (300 m thick) shoreface transgressive (TST) and highstand system tracts (HST) of the Cowlitz Formation range in age from 41.5-41.2 Ma to 39.35 ±0.36 Ma. The Cowlitz Formation HST of the study area chronostratigraphically correlates to the reservoir Clark arid Wilson sandstone member of the Mist Gas Field Cowlitz Formation and to informal unit 1A and lower unit lB of the type-Cowlitz Formation, southwest Washington. The Grays River Volcanics of the study area are subdivided by an intraformational unconformity defining the upper (~150-m thick; 38.6-36.8 Ma) and lower (1250-m thick; 40.1-39 Ma) Grays River Volcanics subunits. Two subalkaline olivine- augite tholeiitic basalt flows of the lower Grays River Volcanics conformably overlying the Cowlitz Formation in Germany Creek were 40Ar/39Ar dated at 40.09 ±0.34 Ma and 39.35 ±0.36 Ma. The tholeiitic upper Grays River basalt unconformably overlies the lower Grays River Volcanics and the Cowlitz Formation. Numerous sub-parallel, northeast and minor northwest trending Grays River dikes (40Ar/39Ar dated at 39.98 ±0.29 and 39.56 ±0.41 Ma) attest to extension of the study area during the eruption of the Grays River Volcanics. The Oligocene Lincoln Creek Formation (~70m) consists of bioturbated tuffaceous siltstone and interbedded silty sandstone with casts and molds of articulated mollusks. Geochemistry, normal polarity, and dikytaxitic texture of the 50-60 m thick Grande Ronde basalt are indicative of the Sentinel Bluffs unit (15.6 Ma) (Columbia River Basalt Group). The Arkansas Anticline and three fault sets: (1) north-northwest- and (2) northwest-trending dextral oblique-slip faults, and (3) subordinate northeast-trending conjugate sinistral oblique-slip faults are related to two periods of deformation. They are: (1) dextral transtension resulting in horst and graben style faulting, beginning 40-39.5 Ma and terminating prior to the eruption of the upper Grays River volcanics (38.6 Ma); (2) post-middle Miocene period of dextral transpression, including dextral reactivation of normal faults and associated broad regional northwest-trending folding (e.g. Arkansas Anticline). Small normal fault block similar to the Mist Gas Field provide structural traps throughout southwest Washington. Petrography of micaceous lithic arkoses of the upper McIntosh sandstone and Cowlitz Formation indicates reservoir-quality sandstones with an estimated porosity of 16-19%. The most likely hydrocarbon exploration play involves the subtidal to shoreface upper McIntosh Formation sandstone member. Title: Sequence stratigraphy and lithofacies of the middle Eocene upper McIntosh and Cowlitz Formations, geology of the Grays River Volcanics, Castle Rock - Germany Creek area, southwest Washington Author: Kleibacker, Derik W. A composite 732-rn thick section in Germany Creek of middle Eocene upper McIntosh and lower Cowlitz Formations, as well as the lower Grays River Volcanics, was studied using bio-, magneto- and lithostratigraphy to construct a sequence stratigraphic framework and assess hydrocarbon exploration potential. The upper McIntosh Formation forms a complete 3rd order depositional cycle that includes shallow marine, tide- and wave-dominated sandstones (upper McIntosh sandstone member) and overlying bathyal to outer-shelf siltstone (upper Mcintosh siltsone member). The upper McIntosh Formation coffelates to Chrons C19r (41.5 -42.5 Ma) and lower Chron 19n (41.5-41.2 Ma). A 31 order sequence boundary straddling Chron 19n (41.2-41.5 Ma) shows truncation of the highstand upper McIntosh siltstone by prograding lowstand shoreface parasequences of the lower Cowlitz Formation. The overlying (300 m thick) shoreface transgressive (TST) and highstand system tracts (HST) of the Cowlitz Formation range in age from 41.5-41.2 Ma to 39.35 ±0.36 Ma. The Cowlitz Formation HST of the study area chronostratigraphically correlates to the reservoir Clark arid Wilson sandstone member of the Mist Gas Field Cowlitz Formation and to informal unit 1A and lower unit lB of the type-Cowlitz Formation, southwest Washington. The Grays River Volcanics of the study area are subdivided by an intraformational unconformity defining the upper (~150-m thick; 38.6-36.8 Ma) and lower (1250-m thick; 40.1-39 Ma) Grays River Volcanics subunits. Two subalkaline olivine- augite tholeiitic basalt flows of the lower Grays River Volcanics conformably overlying the Cowlitz Formation in Germany Creek were 40Ar/39Ar dated at 40.09 ±0.34 Ma and 39.35 ±0.36 Ma. The tholeiitic upper Grays River basalt unconformably overlies the lower Grays River Volcanics and the Cowlitz Formation. Numerous sub-parallel, northeast and minor northwest trending Grays River dikes (40Ar/39Ar dated at 39.98 ±0.29 and 39.56 ±0.41 Ma) attest to extension of the study area during the eruption of the Grays River Volcanics. The Oligocene Lincoln Creek Formation (~70m) consists of bioturbated tuffaceous siltstone and interbedded silty sandstone with casts and molds of articulated mollusks. Geochemistry, normal polarity, and dikytaxitic texture of the 50-60 m thick Grande Ronde basalt are indicative of the Sentinel Bluffs unit (15.6 Ma) (Columbia River Basalt Group). The Arkansas Anticline and three fault sets: (1) north-northwest- and (2) northwest-trending dextral oblique-slip faults, and (3) subordinate northeast-trending conjugate sinistral oblique-slip faults are related to two periods of deformation. They are: (1) dextral transtension resulting in horst and graben style faulting, beginning 40-39.5 Ma and terminating prior to the eruption of the upper Grays River volcanics (38.6 Ma); (2) post-middle Miocene period of dextral transpression, including dextral reactivation of normal faults and associated broad regional northwest-trending folding (e.g. Arkansas Anticline). Small normal fault block similar to the Mist Gas Field provide structural traps throughout southwest Washington. Petrography of micaceous lithic arkoses of the upper McIntosh sandstone and Cowlitz Formation indicates reservoir-quality sandstones with an estimated porosity of 16-19%. The most likely hydrocarbon exploration play involves the subtidal to shoreface upper McIntosh Formation sandstone member. Close

• 47. [Article] Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon

  Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River ...

  Citation × Citation Citation Abstract Copy Title: Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon Author: Sollid, Sarah A. Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects of M. cerebralis on resident and anadromous salmonids in Oregon. Laboratory challenges to determine the susceptibility of indigenous Deschutes River, Oregon, salmonids to M. cerebralis were conducted as part of a study to assess the risk of reintroducing anadromous salmon above a migration barrier on that river. This study was the first to assess the susceptibility of kokanee salmon Oncorhynchus nerka to M. cerebralis, and results contribute to the understanding of salmonid susceptibility as it relates to species and age. Further, this study demonstrates that the indigenous salmonids present in the river are susceptible to infection, but resident rainbow trout Oncorhynchus mykiss would be most at risk should introduction of M. cerebralis occur in this system. The susceptibility of chinook salmon Oncorhynchus tshawytscha to M. cerebralis was assessed following laboratory challenges at different ages to different parasite levels. Results from this study indicate that chinook salmon are more resistant to M. cerebralis infection than susceptible rainbow trout; resistance to disease developed in chinook salmon exposed after 3 weeks of age. Sustained exposures to a low parasite dose were performed to model the conditions chinook salmon would encounter in a natural exposure. Following continuous exposure to low parasite densities, chinook salmon were very resistant to infection and disease. Managed populations of chinook salmon and steelhead Oncorhynchus mykiss juveniles are held in acclimation facilities on their natal streams before release to commence their seaward migration. Rainbow trout fry were held at each of the acclimation facilities to detect the presence of M. cerebralis and to assess the prevalence of exposure during the acclimation period. Results from these exposures indicate that the Wallowa acclimation facility is a high-risk site for parasite exposure of steelhead juveniles. Further, detection was confirmed in several rivers and streams where the presence of M. cerebralis has been suggested. Finally, a preliminary study on the effect of M. cerebralis on survival of steelhead juveniles upon transfer to saltwater was conducted. Results from this study indicate that M. cerebralis exposure and infection may increase mortality among juvenile steelhead during saltwater adaptation. Title: Susceptibility of select salmonids to Myxobolus cerebralis and effects of exposure on anadromous salmonids in Oregon Author: Sollid, Sarah A. Myxobolus cerebralis, a myxozoan parasite of salmonids, is the causative agent of whirling disease. The parasite is considered widespread throughout northeastern Oregon in the Grande Ronde and Imnaha River basins where threatened and endangered salmonid populations exist. The work presented in this thesis comprises several studies that assess the effects of M. cerebralis on resident and anadromous salmonids in Oregon. Laboratory challenges to determine the susceptibility of indigenous Deschutes River, Oregon, salmonids to M. cerebralis were conducted as part of a study to assess the risk of reintroducing anadromous salmon above a migration barrier on that river. This study was the first to assess the susceptibility of kokanee salmon Oncorhynchus nerka to M. cerebralis, and results contribute to the understanding of salmonid susceptibility as it relates to species and age. Further, this study demonstrates that the indigenous salmonids present in the river are susceptible to infection, but resident rainbow trout Oncorhynchus mykiss would be most at risk should introduction of M. cerebralis occur in this system. The susceptibility of chinook salmon Oncorhynchus tshawytscha to M. cerebralis was assessed following laboratory challenges at different ages to different parasite levels. Results from this study indicate that chinook salmon are more resistant to M. cerebralis infection than susceptible rainbow trout; resistance to disease developed in chinook salmon exposed after 3 weeks of age. Sustained exposures to a low parasite dose were performed to model the conditions chinook salmon would encounter in a natural exposure. Following continuous exposure to low parasite densities, chinook salmon were very resistant to infection and disease. Managed populations of chinook salmon and steelhead Oncorhynchus mykiss juveniles are held in acclimation facilities on their natal streams before release to commence their seaward migration. Rainbow trout fry were held at each of the acclimation facilities to detect the presence of M. cerebralis and to assess the prevalence of exposure during the acclimation period. Results from these exposures indicate that the Wallowa acclimation facility is a high-risk site for parasite exposure of steelhead juveniles. Further, detection was confirmed in several rivers and streams where the presence of M. cerebralis has been suggested. Finally, a preliminary study on the effect of M. cerebralis on survival of steelhead juveniles upon transfer to saltwater was conducted. Results from this study indicate that M. cerebralis exposure and infection may increase mortality among juvenile steelhead during saltwater adaptation. Close

• 48. [Article] Spatial patterns of fuel management activities and their effects on wildfire behavior

  Fuel management has been used as an effective local strategy to reduce the undesirable consequences of wildfires. Many efforts toward scheduling of fuel management activities across a broader landscape ...

  Citation × Citation Citation Abstract Copy Title: Spatial patterns of fuel management activities and their effects on wildfire behavior Author: Kim, Young-Hwan Fuel management has been used as an effective local strategy to reduce the undesirable consequences of wildfires. Many efforts toward scheduling of fuel management activities across a broader landscape have been proposed, with the hope of achieving larger landscape-scale management effects. However, scheduling of fuel management treatments across the broader landscape is limited by understandings of how individual management activities aggregate to larger scales and how they affect the behavior of wildfires. Since full coverage of a landscape with fuels management treatments is unlikely, it is necessary to examine the effects of a spatial pattern of individual management activities at the landscape scale. In this research, four spatial patterns of fuel management activities – dispersed, clumped, random, and regular – were tested to investigate their potential for reducing the risk of severe wildfire. A new methodology was developed for optimizing fuel management patterns across a landscape based on a heuristic technique and GIS databases. To quantify the cumulative effects of fuel management patterns for disrupting the progress of wildfires, overall flame length, fireline intensity, and fire size were measured for simulated fires, using a fire growth simulation model, FARSITE. The management scenarios generated from the scheduling model presented a variety of dispersion and treatment sizes, but also evenly distributed the harvest volume through the multi-decade time horizon. The optimized spatial patterns were qualified through visual examination as well as a statistical assessment. Through this research, I have learned that the efficiency of fuels management activities for reducing severity of wildfire is primarily influenced by treatment size, type, and intensity. Most importantly, treatment types and intensity are the critical factor to disrupt human-caused wildfires. The regular pattern seemed to be the most acceptable for either random ignitions or hypothetical human-caused ignitions. It provided the highest frequency in which simulated fires could contact the treated units, and higher treatment intensity measured by amount of harvested volume from a unit area. To enhance the results of this research, we suggest that one should utilize more feasible management prescriptions for post-fire fuel conditions, and expand ignition sources to other type of human-caused ignitions or natural-caused ignitions. Title: Spatial patterns of fuel management activities and their effects on wildfire behavior Author: Kim, Young-Hwan Fuel management has been used as an effective local strategy to reduce the undesirable consequences of wildfires. Many efforts toward scheduling of fuel management activities across a broader landscape have been proposed, with the hope of achieving larger landscape-scale management effects. However, scheduling of fuel management treatments across the broader landscape is limited by understandings of how individual management activities aggregate to larger scales and how they affect the behavior of wildfires. Since full coverage of a landscape with fuels management treatments is unlikely, it is necessary to examine the effects of a spatial pattern of individual management activities at the landscape scale. In this research, four spatial patterns of fuel management activities – dispersed, clumped, random, and regular – were tested to investigate their potential for reducing the risk of severe wildfire. A new methodology was developed for optimizing fuel management patterns across a landscape based on a heuristic technique and GIS databases. To quantify the cumulative effects of fuel management patterns for disrupting the progress of wildfires, overall flame length, fireline intensity, and fire size were measured for simulated fires, using a fire growth simulation model, FARSITE. The management scenarios generated from the scheduling model presented a variety of dispersion and treatment sizes, but also evenly distributed the harvest volume through the multi-decade time horizon. The optimized spatial patterns were qualified through visual examination as well as a statistical assessment. Through this research, I have learned that the efficiency of fuels management activities for reducing severity of wildfire is primarily influenced by treatment size, type, and intensity. Most importantly, treatment types and intensity are the critical factor to disrupt human-caused wildfires. The regular pattern seemed to be the most acceptable for either random ignitions or hypothetical human-caused ignitions. It provided the highest frequency in which simulated fires could contact the treated units, and higher treatment intensity measured by amount of harvested volume from a unit area. To enhance the results of this research, we suggest that one should utilize more feasible management prescriptions for post-fire fuel conditions, and expand ignition sources to other type of human-caused ignitions or natural-caused ignitions. Close

• 49. [Article] Fish movement and assemblage dynamics in a Pacific Northwest riverscape

  This study examined fish movements and assemblage dynamics in the Wenaha, Grande Ronde, Snake river system of northeast Oregon and southeast Washington. I investigated the role of fish movement in the ...

  Citation × Citation Citation Abstract Copy Title: Fish movement and assemblage dynamics in a Pacific Northwest riverscape Author: Baxter, Colden V. This study examined fish movements and assemblage dynamics in the Wenaha, Grande Ronde, Snake river system of northeast Oregon and southeast Washington. I investigated the role of fish movement in the dynamics of stream fish assemblages and evaluated relationships between species movement, assemblage structure, and the heterogeneity of habitat at multiple scales within the river network. In doing so, I employed a landscape approach, visualizing the heterogeneity and dynamics of the system as a "riverscape" that sets the stage for the ecology of stream fishes. I quantified fish assemblage dynamics, characterized the nature and extent of movement by representative fish species, and assessed spatial and temporal heterogeneity of stream habitat within the river network. I applied multiple methods, including underwater fish surveys and radio telemetry, and used multiple sampling approaches that allowed me to detect patterns at nested spatial and temporal scales. I found that spatial patterns in fish assemblage structure were highly dynamic over seasonal to diel temporal scales. Seasonal changes in fish assemblage patterns along the length of the river system were primarily driven by the migration of native fishes such as mountain whitefish, bull trout, and largescale suckers. These highly migratory species exhibited a diverse array of movement strategies and often had annual ranges of hundreds of kilometers. The movement of fishes at smaller spatial scales influenced diel dynamics of fish assemblage patterns. Important habitat features at stream, valley segment and channel unit scales were separated spatially, and fish species exhibited a variety of migratory strategies that reflected the complementary use of habitats distributed throughout the riverscape. The importance of fish migration and the dynamic nature of stream fish assemblages and fish habitat relationships should be taken into account in research and conservation of stream fishes. Current conceptual frameworks for stream fish assemblages do not fully reflect the temporal complexity of stream fish life histories or the spatial heterogeneity of stream habitat. I introduce an alternative framework by integrating fish movement into a dynamic perspective of assemblages set within the context of the riverscape, and raise questions regarding the nature of ecological communities. Title: Fish movement and assemblage dynamics in a Pacific Northwest riverscape Author: Baxter, Colden V. This study examined fish movements and assemblage dynamics in the Wenaha, Grande Ronde, Snake river system of northeast Oregon and southeast Washington. I investigated the role of fish movement in the dynamics of stream fish assemblages and evaluated relationships between species movement, assemblage structure, and the heterogeneity of habitat at multiple scales within the river network. In doing so, I employed a landscape approach, visualizing the heterogeneity and dynamics of the system as a "riverscape" that sets the stage for the ecology of stream fishes. I quantified fish assemblage dynamics, characterized the nature and extent of movement by representative fish species, and assessed spatial and temporal heterogeneity of stream habitat within the river network. I applied multiple methods, including underwater fish surveys and radio telemetry, and used multiple sampling approaches that allowed me to detect patterns at nested spatial and temporal scales. I found that spatial patterns in fish assemblage structure were highly dynamic over seasonal to diel temporal scales. Seasonal changes in fish assemblage patterns along the length of the river system were primarily driven by the migration of native fishes such as mountain whitefish, bull trout, and largescale suckers. These highly migratory species exhibited a diverse array of movement strategies and often had annual ranges of hundreds of kilometers. The movement of fishes at smaller spatial scales influenced diel dynamics of fish assemblage patterns. Important habitat features at stream, valley segment and channel unit scales were separated spatially, and fish species exhibited a variety of migratory strategies that reflected the complementary use of habitats distributed throughout the riverscape. The importance of fish migration and the dynamic nature of stream fish assemblages and fish habitat relationships should be taken into account in research and conservation of stream fishes. Current conceptual frameworks for stream fish assemblages do not fully reflect the temporal complexity of stream fish life histories or the spatial heterogeneity of stream habitat. I introduce an alternative framework by integrating fish movement into a dynamic perspective of assemblages set within the context of the riverscape, and raise questions regarding the nature of ecological communities. Close

• 50. [Article] Stratigraphy and sedimentology of the middle eocene Cowlitz Formation and adjacent sedimentary and volcanic units in the Longview-Kelso area, southwest Washington

  Geologic mapping of the Longview-Kelso area and the measurement and description of a composite 650-meter thick stratigraphic section of the Cowlitz Formation (Tc) in Coal Creek using bio-, magneto-, litho-, ...

  Citation × Citation Citation Abstract Copy Title: Stratigraphy and sedimentology of the middle eocene Cowlitz Formation and adjacent sedimentary and volcanic units in the Longview-Kelso area, southwest Washington Author: McCutcheon, Mark S. Geologic mapping of the Longview-Kelso area and the measurement and description of a composite 650-meter thick stratigraphic section of the Cowlitz Formation (Tc) in Coal Creek using bio-, magneto-, litho-, and sequence stratigraphy reveals a complex interplay of Cowlitz micaceous, lithic arkosic shelf to tidal/estuarine to delta plain facies associations, and Grays River basalt lava flows and interbedded basalt volcaniclastics from nearby Grays River eruptive centers (e.g., Mt. Solo and Rocky Point). The lower 100 meters of the Coal Creek section (informal unit 1, Chron 18r) consists of micaceous, lithic arkosic sandstone and siltstone and minor coals, was deposited as part of a highstand system tract (HST) at the base of 3rd order cycle number 3. This unit consists of four dominantly tidal shoaling-upward arkosic sandstone parasequences reflecting upper shoreface to delta plain depositional environments. The overlying unit 2 (Chron 18n) is defined by abundant Grays River basalt volcaniclastic interbeds that intertongue with Cowlitz lithic arkoses. This unit represents the latter part of 3rd order cycle 3, and consists of mostly fining- and thinning-upward parasequences of middle shoreface to delta plain successions of an aggradational to transgressive parasequence set. Near the top of unit 2 is a maximum marine flooding surface depositing lower shoreface lithic arkosic sandstone to shelf siltstones over upper shoreface micaceous lithic arkose. Unit 3 comprises 3rd order cycle 4 (Chron 17r), a lowstand system tract, and consists of 6 mostly fining- and thinning-upward parasequences of lower shoreface to delta plain facies associations. A parasequence or erosional boundary at the base of unit 5 (Chron 17r) consists of submarine channel-fill scoured into underlying micaceous siltstones, produced during a lowstand system tract (LST) of 3rd order cycle 5. This deep marine channel-fill sequence is overlain by thinlybedded to laminated overbank distal turbidites and hemipelagic siltstones that define the top of the Coal Creek section. These 5 informal units in Coal Creek lithologically and chronologically correlate to 5 similar informal units defined by Payne (1998) in the type section of Cowlitz Formation in Olequa Creek near Vader -30 km to the north. Middle Eocene Grays River Volcanics of the study area are mapped as two separate units: a lower unit over 150 meters thick in places, consisting of subaerial basaltic flows and invasive flows (Tgvl), intrusions (Tgvis and Tgvid), and volcaniclastics (Tgvsl); and an upper unit consisting of commonly mollusk-bearing, shallow marine basaltic sedimentary interbeds that intertongue with the Cowlitz Formation (Tgvs2), particularly Cowlitz unit 2 of the Coal Creek section. These volcaniclastic deposits are intrabasinal, derived from volcanic highlands to the west and northwest, and local phreatomagmatic tuff cones. The lower Grays River volcaniclastic unit typically overlies Grays River flows in the study area and is divided into 5 informal facies. Geochemically, Grays River flows in the study area fall within normal parameters (3 to 4% TiO2 and high iron tholeiitic basalts). However, basalt flows and bedded scoriaceous breccias near Rocky Point are anomalously low in TiO2 and are considered in this study to be a separate volcanic subunit (Rocky Point Basalts), time equivalent to and interfingering with Grays River lavas, but may represent mixing with shallower western Cascade calc-alkaline magma. Over 60 younger Grays River dikes intrude the Cowlitz Formation in Coal Creek. A dike low in the Coal Creek section is dated at 40 ± 0.36 Ma, and an invasive flow at Mt. Solo is dated at 36.98 ±.78 Ma. Volcanics capping the hills east of the Cowlitz River are chemically distinct as slightly younger western Cascade basaltic andesite flows, and two dikes east of the river are chemically distinct as western Cascade andesite. Overlying Grays River Volcanics and Cowlitz Formation in much of the study area, are clayey and commonly tuffaceous siltstones and silty sandstones, possibly of the late Eocene-early Oligocene Toutle Formation, a new unit to this area. The Toutle Formation is a mixture of wave and stream reworked micaceous and arkosic Cowlitz Formation and fresh silicic pyroclastic ash and pumice from the active western Cascade arc. An angular unconformity separates the Paleogene Grays River Volcanics, Cowlitz Formation, and Toutle Formation from the early to middle Miocene Columbia River Basalt Group. Based on lithology, geochemistry, stratigraphic relationships, and magnetic polarity, 6 individual Columbia River Basalt flows have been mapped in this study. The three lower Grande Ronde flows are of normal polarity and Ortley low MgO chemical composition. The lowermost flow (N2 Ortley #1) is absent in the Columbia Heights area, low MgO, about 10 meters thick and consists of pillow-palagonite sequences in the upper quarry on Mt. Solo. Aphyric N2 Ortley flow #2 is over 35 meters thick with well-developed upper and lower colonnade, and of intermediate MgO. N2 Ortley flow #3 is pillow-palagonite in the Storedahl Quarry and low MgO. A -4-meter thick tuffaceous overbank siltstone and basalt conglomeratic channel interbed separates the three low MgO Ortley flows from the overlying high MgO N2 Grande Ronde Sentinel Bluffs flow. A single exposure of well-developed large colonnade with sparse 1 cm labradorite laths, and reddish oxidized soil, defines the N Sand Hollow flow of the Frenchman Springs Member of the Wanapum Formation. The overlying Pomona Member is mapped based on previous work by other authors. Pliocene gravels and arkosic sand of the Troutdale Formation form upland terrace deposits up to 100 meters thick in southern parts of the study area, and represent the uplifted paleo-thalweg and overbank flood deposits of the downcutting, antecedent ancestral Columbia River. Well-rounded clasts are a mixture of extrabasinal granitic and metamorphic quartzite, and intrabasinal porphyritic basaltic andesite, dacite, and basalt from the western Cascades and Columbia River Basalts. Troutdale terrace gravels grade northward into contemporaneous volcanic pebble and cobble gravel terrace deposits produced along the ancestral Cowlitz River that are dominantly composed of porphyritic andesite gravel and volcanic sand from the western Cascades. Lower terraces along the Cowlitz River were deposited by the late Pleistocene Missoula Floods. All of these unconsolidated to semiconsolidated gravels and sands are prone to landslides, and the Aldercrest-Banyon landslide, the second worst landslide disaster in American history, occurred in the Troutdale Formation gravels. After eruption of the Grays River Volcanics and deposition of the Cowlitz Formation, the forearc underwent a period of transtension in the late-middle Eocene related to magmatic upwelling and reorganization of the subducting Farallon Plate. This event produced a northwest-trending set of oblique slip normal faults, along which Grays River dikes intruded. Starting in the early Miocene the region underwent a transpressional event, reactivating many of the northwest-trending faults, and producing the Columbia Heights Anticline, Hazel Dell Syncline, the Coal Creek Fault, and the Kelso Fault Zone. The paleotopography resulting from this event was stream eroded to a nearly flat plain before emplacement of the Columbia River Basalts, which are nearly horizontal today. Continued offset along the northwest-trending fault set has also offset the Columbia River Basalts. Continued oblique slip post-Miocene broad arching of the Coast Range and downcutting by the Columbia and Cowlitz Rivers has resulted in Pliocene and Pleistocene terraces, and produced an east-west fault set that offsets all earlier structural features. Title: Stratigraphy and sedimentology of the middle eocene Cowlitz Formation and adjacent sedimentary and volcanic units in the Longview-Kelso area, southwest Washington Author: McCutcheon, Mark S. Geologic mapping of the Longview-Kelso area and the measurement and description of a composite 650-meter thick stratigraphic section of the Cowlitz Formation (Tc) in Coal Creek using bio-, magneto-, litho-, and sequence stratigraphy reveals a complex interplay of Cowlitz micaceous, lithic arkosic shelf to tidal/estuarine to delta plain facies associations, and Grays River basalt lava flows and interbedded basalt volcaniclastics from nearby Grays River eruptive centers (e.g., Mt. Solo and Rocky Point). The lower 100 meters of the Coal Creek section (informal unit 1, Chron 18r) consists of micaceous, lithic arkosic sandstone and siltstone and minor coals, was deposited as part of a highstand system tract (HST) at the base of 3rd order cycle number 3. This unit consists of four dominantly tidal shoaling-upward arkosic sandstone parasequences reflecting upper shoreface to delta plain depositional environments. The overlying unit 2 (Chron 18n) is defined by abundant Grays River basalt volcaniclastic interbeds that intertongue with Cowlitz lithic arkoses. This unit represents the latter part of 3rd order cycle 3, and consists of mostly fining- and thinning-upward parasequences of middle shoreface to delta plain successions of an aggradational to transgressive parasequence set. Near the top of unit 2 is a maximum marine flooding surface depositing lower shoreface lithic arkosic sandstone to shelf siltstones over upper shoreface micaceous lithic arkose. Unit 3 comprises 3rd order cycle 4 (Chron 17r), a lowstand system tract, and consists of 6 mostly fining- and thinning-upward parasequences of lower shoreface to delta plain facies associations. A parasequence or erosional boundary at the base of unit 5 (Chron 17r) consists of submarine channel-fill scoured into underlying micaceous siltstones, produced during a lowstand system tract (LST) of 3rd order cycle 5. This deep marine channel-fill sequence is overlain by thinlybedded to laminated overbank distal turbidites and hemipelagic siltstones that define the top of the Coal Creek section. These 5 informal units in Coal Creek lithologically and chronologically correlate to 5 similar informal units defined by Payne (1998) in the type section of Cowlitz Formation in Olequa Creek near Vader -30 km to the north. Middle Eocene Grays River Volcanics of the study area are mapped as two separate units: a lower unit over 150 meters thick in places, consisting of subaerial basaltic flows and invasive flows (Tgvl), intrusions (Tgvis and Tgvid), and volcaniclastics (Tgvsl); and an upper unit consisting of commonly mollusk-bearing, shallow marine basaltic sedimentary interbeds that intertongue with the Cowlitz Formation (Tgvs2), particularly Cowlitz unit 2 of the Coal Creek section. These volcaniclastic deposits are intrabasinal, derived from volcanic highlands to the west and northwest, and local phreatomagmatic tuff cones. The lower Grays River volcaniclastic unit typically overlies Grays River flows in the study area and is divided into 5 informal facies. Geochemically, Grays River flows in the study area fall within normal parameters (3 to 4% TiO2 and high iron tholeiitic basalts). However, basalt flows and bedded scoriaceous breccias near Rocky Point are anomalously low in TiO2 and are considered in this study to be a separate volcanic subunit (Rocky Point Basalts), time equivalent to and interfingering with Grays River lavas, but may represent mixing with shallower western Cascade calc-alkaline magma. Over 60 younger Grays River dikes intrude the Cowlitz Formation in Coal Creek. A dike low in the Coal Creek section is dated at 40 ± 0.36 Ma, and an invasive flow at Mt. Solo is dated at 36.98 ±.78 Ma. Volcanics capping the hills east of the Cowlitz River are chemically distinct as slightly younger western Cascade basaltic andesite flows, and two dikes east of the river are chemically distinct as western Cascade andesite. Overlying Grays River Volcanics and Cowlitz Formation in much of the study area, are clayey and commonly tuffaceous siltstones and silty sandstones, possibly of the late Eocene-early Oligocene Toutle Formation, a new unit to this area. The Toutle Formation is a mixture of wave and stream reworked micaceous and arkosic Cowlitz Formation and fresh silicic pyroclastic ash and pumice from the active western Cascade arc. An angular unconformity separates the Paleogene Grays River Volcanics, Cowlitz Formation, and Toutle Formation from the early to middle Miocene Columbia River Basalt Group. Based on lithology, geochemistry, stratigraphic relationships, and magnetic polarity, 6 individual Columbia River Basalt flows have been mapped in this study. The three lower Grande Ronde flows are of normal polarity and Ortley low MgO chemical composition. The lowermost flow (N2 Ortley #1) is absent in the Columbia Heights area, low MgO, about 10 meters thick and consists of pillow-palagonite sequences in the upper quarry on Mt. Solo. Aphyric N2 Ortley flow #2 is over 35 meters thick with well-developed upper and lower colonnade, and of intermediate MgO. N2 Ortley flow #3 is pillow-palagonite in the Storedahl Quarry and low MgO. A -4-meter thick tuffaceous overbank siltstone and basalt conglomeratic channel interbed separates the three low MgO Ortley flows from the overlying high MgO N2 Grande Ronde Sentinel Bluffs flow. A single exposure of well-developed large colonnade with sparse 1 cm labradorite laths, and reddish oxidized soil, defines the N Sand Hollow flow of the Frenchman Springs Member of the Wanapum Formation. The overlying Pomona Member is mapped based on previous work by other authors. Pliocene gravels and arkosic sand of the Troutdale Formation form upland terrace deposits up to 100 meters thick in southern parts of the study area, and represent the uplifted paleo-thalweg and overbank flood deposits of the downcutting, antecedent ancestral Columbia River. Well-rounded clasts are a mixture of extrabasinal granitic and metamorphic quartzite, and intrabasinal porphyritic basaltic andesite, dacite, and basalt from the western Cascades and Columbia River Basalts. Troutdale terrace gravels grade northward into contemporaneous volcanic pebble and cobble gravel terrace deposits produced along the ancestral Cowlitz River that are dominantly composed of porphyritic andesite gravel and volcanic sand from the western Cascades. Lower terraces along the Cowlitz River were deposited by the late Pleistocene Missoula Floods. All of these unconsolidated to semiconsolidated gravels and sands are prone to landslides, and the Aldercrest-Banyon landslide, the second worst landslide disaster in American history, occurred in the Troutdale Formation gravels. After eruption of the Grays River Volcanics and deposition of the Cowlitz Formation, the forearc underwent a period of transtension in the late-middle Eocene related to magmatic upwelling and reorganization of the subducting Farallon Plate. This event produced a northwest-trending set of oblique slip normal faults, along which Grays River dikes intruded. Starting in the early Miocene the region underwent a transpressional event, reactivating many of the northwest-trending faults, and producing the Columbia Heights Anticline, Hazel Dell Syncline, the Coal Creek Fault, and the Kelso Fault Zone. The paleotopography resulting from this event was stream eroded to a nearly flat plain before emplacement of the Columbia River Basalts, which are nearly horizontal today. Continued offset along the northwest-trending fault set has also offset the Columbia River Basalts. Continued oblique slip post-Miocene broad arching of the Coast Range and downcutting by the Columbia and Cowlitz Rivers has resulted in Pliocene and Pleistocene terraces, and produced an east-west fault set that offsets all earlier structural features. Close