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• 1. [Article] Stratigraphic relationships of the Tillamook Volcanics and the Cowlitz Formation in the upper Nehalem River-Wolf Creek area, northwestern Oregon

  The upper Nehalem River-Wolf Creek area is located on the northeastern flank of the Tillamook Highlands in the northern Oregon Coast Range. Three rock stratigraphic units underlie the thesis area, and ...

  Citation × Citation Citation Abstract Copy Title: Stratigraphic relationships of the Tillamook Volcanics and the Cowlitz Formation in the upper Nehalem River-Wolf Creek area, northwestern Oregon Author: Jackson, Michael Keith Year: 1983 The upper Nehalem River-Wolf Creek area is located on the northeastern flank of the Tillamook Highlands in the northern Oregon Coast Range. Three rock stratigraphic units underlie the thesis area, and these units range from late Eocene to Oligocene in age. Title: Stratigraphic relationships of the Tillamook Volcanics and the Cowlitz Formation in the upper Nehalem River-Wolf Creek area, northwestern Oregon Author: Jackson, Michael Keith Year: 1983 The upper Nehalem River-Wolf Creek area is located on the northeastern flank of the Tillamook Highlands in the northern Oregon Coast Range. Three rock stratigraphic units underlie the thesis area, and these units range from late Eocene to Oligocene in age. Close

• 2. [Article] Geochemical Evolution of Ferruginous Bauxite Deposits in Northwestern Oregon and Southwestern Washington

  Ferruginous bauxite deposits developed from flows of the Columbia River Basalt Group in northwestern Oregon and southwestern Washington. Samples of the iron pisolite and the gibbsite nodular zones from ...

  Citation × Citation Citation Abstract Copy Title: Geochemical Evolution of Ferruginous Bauxite Deposits in Northwestern Oregon and Southwestern Washington Author: Fassio, Joseph Michael Year: 1990 Ferruginous bauxite deposits developed from flows of the Columbia River Basalt Group in northwestern Oregon and southwestern Washington. Samples of the iron pisolite and the gibbsite nodular zones from the upper portion of the weathering profile of drill core from Columbia County, Oregon and Cowlitz County, Washington, were analyzed by instrumental neutron activation. The mineralogy was determined using Xray diffraction and Mossbauer spectroscopy. The gibbsite nodular zone is above the clay-rich saprolite or relic basalt zone. The nodules contain relic vesicles and well preserved relic plagioclase microlites. Gibbsite occurs with poorly crystalline goethite and hematite in the gibbsite nodular zone. Clays are absent in this part of the profile . The iron pisolite zone is at the top of the profile above the gibbsite nodular zone. Both maghemite and goethite pisolites occur in the lower part of the zone while maghemite pisolites are dominant in the upper part of the pisolite zone. The parent flow is the Frenchman Springs Member of the Wanapum Basalt for the Columbia County profile and the Pomona Member of the Saddle Mountains Basalt for the Cowlitz County profile. Distribution of the major, minor and trace elements through the profile shows three distinct sympathetic patterns consisting of lanthanide elements and Na; As, Sbi Th, Hf, and Ta; and transition metals Fe, Ti, V, and Cr. Ratios between the high-field strength elements Ta and Hf are nearly constant through the profile, and Hf appears to be the least mobile elements of the elements analyzed in the profile. Ratios of other elements were calculated against Hf, based on the assumption that it has remained largely immobile during weathering, to show element enrichment and depletion in the profile independent of mass-volume changes. Transition metals and Al show a progressive depletion through the upper gibbsite nodular and iron pisolite zone due to leaching in the profile. Lanthanide elements (except Ce), As, and Sb show an obvious enrichment in the iron pisolite zone relative to the gibbsite nodular zone. Volume reduction during weathering was calculated based on the immobility of Hf. In the gibbsite nodular zone, the volume reduction calculated for bulk samples is greater than for gibbsite nodule separates suggesting that a greater volume reduction occurred the matrix material surrounding the nodules. Ratios between gibbsite nodules and parent basalt of the immobile elements Hf, Ta, Fe, Ti, Th and Cr suggest that the nodules, where the relic textures are preserved, have undergone volume reduction. Based on the immobility of Hf, the gibbsite nodules lost approximately 40% of the original volume. The volume factors based on the immobility of Hf show that the pisolite zone experienced a greater volume reduction than the gibbsite nodular zone. Absolute gains and losses relative to the parent basalt show the following relative order of depletion: Na > La > Eu > Sm > Co > Mn > Ce > Sc > Ta > V > Cr > Lu > Th > Fe > Ga > Al. The lesser mobility of Ce and Lu relative to other lanthanide elements suggests fractionation of lanthanide elements in the bauxite profile. Aluminum is both enriched and depleted at different depths in the gibbsite nodular zone suggesting that Al is mobilized from the matrix and possibly the pisolite zone into Al enriched gibbsite nodules. Volume reduction and destruction of relic textures in the pisolite zone is accompanied by small-scale mobilization of Th, Cr, Fe, Hf, Ga, Sc, and Ta during the formation of iron pisolites. Formation of the iron pisolite zone above the gibbsite nodular zone may indicate a change in climate from a heavy year round to a seasonal rainfall pattern. Title: Geochemical Evolution of Ferruginous Bauxite Deposits in Northwestern Oregon and Southwestern Washington Author: Fassio, Joseph Michael Year: 1990 Ferruginous bauxite deposits developed from flows of the Columbia River Basalt Group in northwestern Oregon and southwestern Washington. Samples of the iron pisolite and the gibbsite nodular zones from the upper portion of the weathering profile of drill core from Columbia County, Oregon and Cowlitz County, Washington, were analyzed by instrumental neutron activation. The mineralogy was determined using Xray diffraction and Mossbauer spectroscopy. The gibbsite nodular zone is above the clay-rich saprolite or relic basalt zone. The nodules contain relic vesicles and well preserved relic plagioclase microlites. Gibbsite occurs with poorly crystalline goethite and hematite in the gibbsite nodular zone. Clays are absent in this part of the profile . The iron pisolite zone is at the top of the profile above the gibbsite nodular zone. Both maghemite and goethite pisolites occur in the lower part of the zone while maghemite pisolites are dominant in the upper part of the pisolite zone. The parent flow is the Frenchman Springs Member of the Wanapum Basalt for the Columbia County profile and the Pomona Member of the Saddle Mountains Basalt for the Cowlitz County profile. Distribution of the major, minor and trace elements through the profile shows three distinct sympathetic patterns consisting of lanthanide elements and Na; As, Sbi Th, Hf, and Ta; and transition metals Fe, Ti, V, and Cr. Ratios between the high-field strength elements Ta and Hf are nearly constant through the profile, and Hf appears to be the least mobile elements of the elements analyzed in the profile. Ratios of other elements were calculated against Hf, based on the assumption that it has remained largely immobile during weathering, to show element enrichment and depletion in the profile independent of mass-volume changes. Transition metals and Al show a progressive depletion through the upper gibbsite nodular and iron pisolite zone due to leaching in the profile. Lanthanide elements (except Ce), As, and Sb show an obvious enrichment in the iron pisolite zone relative to the gibbsite nodular zone. Volume reduction during weathering was calculated based on the immobility of Hf. In the gibbsite nodular zone, the volume reduction calculated for bulk samples is greater than for gibbsite nodule separates suggesting that a greater volume reduction occurred the matrix material surrounding the nodules. Ratios between gibbsite nodules and parent basalt of the immobile elements Hf, Ta, Fe, Ti, Th and Cr suggest that the nodules, where the relic textures are preserved, have undergone volume reduction. Based on the immobility of Hf, the gibbsite nodules lost approximately 40% of the original volume. The volume factors based on the immobility of Hf show that the pisolite zone experienced a greater volume reduction than the gibbsite nodular zone. Absolute gains and losses relative to the parent basalt show the following relative order of depletion: Na > La > Eu > Sm > Co > Mn > Ce > Sc > Ta > V > Cr > Lu > Th > Fe > Ga > Al. The lesser mobility of Ce and Lu relative to other lanthanide elements suggests fractionation of lanthanide elements in the bauxite profile. Aluminum is both enriched and depleted at different depths in the gibbsite nodular zone suggesting that Al is mobilized from the matrix and possibly the pisolite zone into Al enriched gibbsite nodules. Volume reduction and destruction of relic textures in the pisolite zone is accompanied by small-scale mobilization of Th, Cr, Fe, Hf, Ga, Sc, and Ta during the formation of iron pisolites. Formation of the iron pisolite zone above the gibbsite nodular zone may indicate a change in climate from a heavy year round to a seasonal rainfall pattern. Close

• 3. [Article] The stratigraphy of the Scappoose formation, the Astoria formation, and the Columbia River basalt group in northwestern Columbia County, Oregon

  The study area is located in northwestern Columbia County, and covers an area of approximately 70 square kilometers. The purpose of the study was to investigate the possible correlation of the Scappoose ...

  Citation × Citation Citation Abstract Copy Title: The stratigraphy of the Scappoose formation, the Astoria formation, and the Columbia River basalt group in northwestern Columbia County, Oregon Author: Ketrenos, Nancy Tompkins Year: 1986 The study area is located in northwestern Columbia County, and covers an area of approximately 70 square kilometers. The purpose of the study was to investigate the possible correlation of the Scappoose and Astoria Formations and determine their stratigraphic relationship to the Columbia River Basalt Group through mapping, geochemistry and petrography. Title: The stratigraphy of the Scappoose formation, the Astoria formation, and the Columbia River basalt group in northwestern Columbia County, Oregon Author: Ketrenos, Nancy Tompkins Year: 1986 The study area is located in northwestern Columbia County, and covers an area of approximately 70 square kilometers. The purpose of the study was to investigate the possible correlation of the Scappoose and Astoria Formations and determine their stratigraphic relationship to the Columbia River Basalt Group through mapping, geochemistry and petrography. Close

• 4. [Article] Preliminary investigation for underground storage of pipeline gas in the Bruer and Flora pools, Mist gas field, Columbia County, Oregon

  Northwest Natural Gas Canpany has proposed to convert the Bruer and Flora pools of the Mist Gas Field in west-central Columbia County, Northwestern Oregon, to pipeline gas storage reservoirs. Conversion ...

  Citation × Citation Citation Abstract Copy Title: Preliminary investigation for underground storage of pipeline gas in the Bruer and Flora pools, Mist gas field, Columbia County, Oregon Author: Townley, Paul Joseph Year: 1985 Northwest Natural Gas Canpany has proposed to convert the Bruer and Flora pools of the Mist Gas Field in west-central Columbia County, Northwestern Oregon, to pipeline gas storage reservoirs. Conversion to underground storage of pipeline gas in these depleted gas reservoirs would be the first in the Pacific Northwest. The Bruer and Flora Pools are fault trapped within the Cowlitz Formation. The shales overlying the Cowlitz Formation create a local seal for these gas reservoirs. X-ray diffraction and density log measurements suggest that the clay in these shales is primarily composed of smectite, which provides an excellent caprock seal. The reservoir rock of the Bruer and Flora Pools is the arkosic Cl ark and Wilson Sand. An average weighted grain density for the sand is 2.65 g/cm3. The abundance of potassium feldspar in the sand, hence K40, creates a background gamma radiation for the sand roughly equal to that of the shale, making the sand and shale virtually indistinguishable on the gamma ray log. Bottan Hole Temperatures (BHT), which were recorded on open hole logs, indicate the Bruer Pool is 7°C (20°F) wanner than the Flora Pool, even though the Flora Pool is deeper. This temperature anomaly may be the result of equipment variation. A calibrated temperature survey would remove any discrepancies. A comparison of the thermal gradient determined in a previous study of the Oregon Coast Range and a gradient determined using BHT, suggest that BHT provide a good approximation of formation temperature. Utilizing the formation water analysis determined from four different wells in the Mist Gas Field, average total dissolved solids was found to be 24, 444 mg/l. Of the four analyses, the sample from Well CC#6 R/D2 is considered to be the most representative of the Bruer and Flora fools formation waters. Analysis of the four samples using the Palmer System suggests that the formation water of the Cowlitz Formation is in the early stages of sea water diagenasis. Formation water resistivity (Rw) was determined using a chemical and spontaneous potential analysis. Rw derived using chemical analysis averaged 0.175 ohm-meters and is considered the ITDst precise. Water saturation determined using the Archie saturation equation averaged 47.5% and ranged from 26.4 to 80.0% for the zone 814-836 meters (2670-2742 feet) in CC#10. These results are similar to those determined by the Thermal Time Decay (TDT) log. Title: Preliminary investigation for underground storage of pipeline gas in the Bruer and Flora pools, Mist gas field, Columbia County, Oregon Author: Townley, Paul Joseph Year: 1985 Northwest Natural Gas Canpany has proposed to convert the Bruer and Flora pools of the Mist Gas Field in west-central Columbia County, Northwestern Oregon, to pipeline gas storage reservoirs. Conversion to underground storage of pipeline gas in these depleted gas reservoirs would be the first in the Pacific Northwest. The Bruer and Flora Pools are fault trapped within the Cowlitz Formation. The shales overlying the Cowlitz Formation create a local seal for these gas reservoirs. X-ray diffraction and density log measurements suggest that the clay in these shales is primarily composed of smectite, which provides an excellent caprock seal. The reservoir rock of the Bruer and Flora Pools is the arkosic Cl ark and Wilson Sand. An average weighted grain density for the sand is 2.65 g/cm3. The abundance of potassium feldspar in the sand, hence K40, creates a background gamma radiation for the sand roughly equal to that of the shale, making the sand and shale virtually indistinguishable on the gamma ray log. Bottan Hole Temperatures (BHT), which were recorded on open hole logs, indicate the Bruer Pool is 7°C (20°F) wanner than the Flora Pool, even though the Flora Pool is deeper. This temperature anomaly may be the result of equipment variation. A calibrated temperature survey would remove any discrepancies. A comparison of the thermal gradient determined in a previous study of the Oregon Coast Range and a gradient determined using BHT, suggest that BHT provide a good approximation of formation temperature. Utilizing the formation water analysis determined from four different wells in the Mist Gas Field, average total dissolved solids was found to be 24, 444 mg/l. Of the four analyses, the sample from Well CC#6 R/D2 is considered to be the most representative of the Bruer and Flora fools formation waters. Analysis of the four samples using the Palmer System suggests that the formation water of the Cowlitz Formation is in the early stages of sea water diagenasis. Formation water resistivity (Rw) was determined using a chemical and spontaneous potential analysis. Rw derived using chemical analysis averaged 0.175 ohm-meters and is considered the ITDst precise. Water saturation determined using the Archie saturation equation averaged 47.5% and ranged from 26.4 to 80.0% for the zone 814-836 meters (2670-2742 feet) in CC#10. These results are similar to those determined by the Thermal Time Decay (TDT) log. Close

• 5. [Article] Field Mapping Investigation and Geochemical Analysis of Volcanic Units within the Dinner Creek Tuff Eruptive Center, Malheur County, Eastern Oregon

  The Dinner Creek Tuff is a mid-Miocene rhyolitic to dacitic ignimbrite, consisting of four cooling units with 40Ar/39Ar ages 16--15 Ma. Previous geologists have suspected that the source of the tuff is ...

  Citation × Citation Citation Abstract Copy Title: Field Mapping Investigation and Geochemical Analysis of Volcanic Units within the Dinner Creek Tuff Eruptive Center, Malheur County, Eastern Oregon Author: Cruz, Matthew Year: 2017 The Dinner Creek Tuff is a mid-Miocene rhyolitic to dacitic ignimbrite, consisting of four cooling units with 40Ar/39Ar ages 16--15 Ma. Previous geologists have suspected that the source of the tuff is located in northwestern Malheur County, eastern Oregon. This broad area is called the Dinner Creek Tuff Eruptive Center. This thesis summarizes field work, XRF/ICP-MS geochemistry, thin section petrography, and SEM feldspar analysis from the summers of 2015 and 2016. The main purpose of this study is to identify sources for the Dinner Creek Tuff units within the Dinner Creek Tuff Eruptive Center. The secondary purpose is to map lave flows that pre-date and post-date the Dinner Creek Tuff, and correlate them with regionally extensive volcanic units. Two volcanic centers related to the Dinner Creek Tuff were identified. The southern volcanic center, centered at Castle Rock, is a caldera and source of the Dinner Creek Tuff unit 1 (DIT1). Rheomorphic, densely welded DIT1 is over 300 m thick along the east side of Castle Rock. The northwestern margin of the caldera has been uplifted along faults, showing vertically foliated tuff dikes and associated mega-breccia deposits. Up to 200 m of incipiently welded tuffs, and fluvial volcanoclastic sediments were deposited on the caldera floor, which has been uplifted due to resurgence and regional extension, creating the complex structural relationships between the volcanic units. The northern volcanic center is located at Ironside Mountain, where densely welded rheomorphic Dinner Creek Tuff unit 2 (DIT2) is exposed in outcrops over 600 m thick. The top of the DIT2 consists of glassy, moderately welded tuff. Sources for the DIT2 are tuff dikes along the south and western flanks of Ironside Mountain. The thick deposits of DIT2 at Ironside Mountain indicate that the mountain is an uplifted caldera, herein named the Ironside Mountain caldera. Uplift may have been due to resurgence, but it is most likely due to normal faulting along the Border Fault, a major regional normal fault that strikes across the northern margin of the caldera. Pre-Dinner Creek Tuff lava flows occur throughout the study area, and can be correlated with the Strawberry Volcanics and the Basalt of Malheur Gorge. A distinct lava flow, herein called the Ring Butte trachy-basalt occurs within the center of the study area, and is distinct from regional lava flows. Following the eruptions of the Dinner Creek Tuff units 1 & 2, aphyric basaltic-andesite and icelandite intrude into, and overlie the intra-caldera tuffs and caldera floor sediments at both calderas. These aphyric lavas are similar in appearance and stratigraphic position with the regionally extensive Hunter Creek basalt. Porphyritic olivine basalt overlies the aphyric Hunter Creek basalt at the Castle Rock caldera. This porphyritic lava is similar in appearance and major/trace element geochemistry to the regional Tim's Peak basalt. Title: Field Mapping Investigation and Geochemical Analysis of Volcanic Units within the Dinner Creek Tuff Eruptive Center, Malheur County, Eastern Oregon Author: Cruz, Matthew Year: 2017 The Dinner Creek Tuff is a mid-Miocene rhyolitic to dacitic ignimbrite, consisting of four cooling units with 40Ar/39Ar ages 16--15 Ma. Previous geologists have suspected that the source of the tuff is located in northwestern Malheur County, eastern Oregon. This broad area is called the Dinner Creek Tuff Eruptive Center. This thesis summarizes field work, XRF/ICP-MS geochemistry, thin section petrography, and SEM feldspar analysis from the summers of 2015 and 2016. The main purpose of this study is to identify sources for the Dinner Creek Tuff units within the Dinner Creek Tuff Eruptive Center. The secondary purpose is to map lave flows that pre-date and post-date the Dinner Creek Tuff, and correlate them with regionally extensive volcanic units. Two volcanic centers related to the Dinner Creek Tuff were identified. The southern volcanic center, centered at Castle Rock, is a caldera and source of the Dinner Creek Tuff unit 1 (DIT1). Rheomorphic, densely welded DIT1 is over 300 m thick along the east side of Castle Rock. The northwestern margin of the caldera has been uplifted along faults, showing vertically foliated tuff dikes and associated mega-breccia deposits. Up to 200 m of incipiently welded tuffs, and fluvial volcanoclastic sediments were deposited on the caldera floor, which has been uplifted due to resurgence and regional extension, creating the complex structural relationships between the volcanic units. The northern volcanic center is located at Ironside Mountain, where densely welded rheomorphic Dinner Creek Tuff unit 2 (DIT2) is exposed in outcrops over 600 m thick. The top of the DIT2 consists of glassy, moderately welded tuff. Sources for the DIT2 are tuff dikes along the south and western flanks of Ironside Mountain. The thick deposits of DIT2 at Ironside Mountain indicate that the mountain is an uplifted caldera, herein named the Ironside Mountain caldera. Uplift may have been due to resurgence, but it is most likely due to normal faulting along the Border Fault, a major regional normal fault that strikes across the northern margin of the caldera. Pre-Dinner Creek Tuff lava flows occur throughout the study area, and can be correlated with the Strawberry Volcanics and the Basalt of Malheur Gorge. A distinct lava flow, herein called the Ring Butte trachy-basalt occurs within the center of the study area, and is distinct from regional lava flows. Following the eruptions of the Dinner Creek Tuff units 1 & 2, aphyric basaltic-andesite and icelandite intrude into, and overlie the intra-caldera tuffs and caldera floor sediments at both calderas. These aphyric lavas are similar in appearance and stratigraphic position with the regionally extensive Hunter Creek basalt. Porphyritic olivine basalt overlies the aphyric Hunter Creek basalt at the Castle Rock caldera. This porphyritic lava is similar in appearance and major/trace element geochemistry to the regional Tim's Peak basalt. Close

• 6. [Article] Biostratigraphy of the type Weberg Member, Snowshoe Formation, Grant County, Oregon

  Thirty three species of ammonites are recorded from the composite type section of the Weberg Member of the Snowshoe Formation in the Suplee area, Grant County, Oregon. Holcophylloceras burkei, Euhoploceras ...

  Citation × Citation Citation Abstract Copy Title: Biostratigraphy of the type Weberg Member, Snowshoe Formation, Grant County, Oregon Author: Taylor, David G. Year: 1977 Thirty three species of ammonites are recorded from the composite type section of the Weberg Member of the Snowshoe Formation in the Suplee area, Grant County, Oregon. Holcophylloceras burkei, Euhoploceras westi, E. tubereulosum and Strigoceras taylori are described as new, while four new species belonging to the genera Sonninia [?], Bradfordia, Pseudotoites and Witchellia are not formally named. Three ammonite zonules characterize the ammonite sequence of the type Weberg composite section. The sequence correlates with parts of the standard lower and middle Bajocian (Jurassic) of northwestern Europe. In addition, four associations (paleo-communities) of benthic mega invertebrates, the Gervillia, Protocardia, Isocyprina and Bositra buahii associations are delineated. The type Weberg composite section is a record of a local marine transgression westward onto an island system. The section also represents sedimentation over an irregular pre-Snowshoe topographic high, and indicates a progressive change from proximal to distal source of pre-Snowshoe sediments, from high to low energy conditions, and perhaps a slight deepening of the ocean bottom. Ammonites are rare in the lower division of the Weberg Member, locally present in fine sandy limestones of the lower part of the upper division, abundant and most diverse in silt-rich, clay-poor limestones of the upper part of the upper division, and locally abundant in mudstones of the Warm Springs Member. Recurrent associations of certain ammonite species, strong correlation of the associations with lithofacies and biofacies, and pervasive faunal differences of ammonites between facies indicate in general that the distributional patterns of the ammonites reflect spatial life-habitats. The spotty yet widespread geographic occurrence of several ammonite species suggest they had undergone extensive planktic dispersal, thus ocean currents probably played an important role in their distributional patterns. Title: Biostratigraphy of the type Weberg Member, Snowshoe Formation, Grant County, Oregon Author: Taylor, David G. Year: 1977 Thirty three species of ammonites are recorded from the composite type section of the Weberg Member of the Snowshoe Formation in the Suplee area, Grant County, Oregon. Holcophylloceras burkei, Euhoploceras westi, E. tubereulosum and Strigoceras taylori are described as new, while four new species belonging to the genera Sonninia [?], Bradfordia, Pseudotoites and Witchellia are not formally named. Three ammonite zonules characterize the ammonite sequence of the type Weberg composite section. The sequence correlates with parts of the standard lower and middle Bajocian (Jurassic) of northwestern Europe. In addition, four associations (paleo-communities) of benthic mega invertebrates, the Gervillia, Protocardia, Isocyprina and Bositra buahii associations are delineated. The type Weberg composite section is a record of a local marine transgression westward onto an island system. The section also represents sedimentation over an irregular pre-Snowshoe topographic high, and indicates a progressive change from proximal to distal source of pre-Snowshoe sediments, from high to low energy conditions, and perhaps a slight deepening of the ocean bottom. Ammonites are rare in the lower division of the Weberg Member, locally present in fine sandy limestones of the lower part of the upper division, abundant and most diverse in silt-rich, clay-poor limestones of the upper part of the upper division, and locally abundant in mudstones of the Warm Springs Member. Recurrent associations of certain ammonite species, strong correlation of the associations with lithofacies and biofacies, and pervasive faunal differences of ammonites between facies indicate in general that the distributional patterns of the ammonites reflect spatial life-habitats. The spotty yet widespread geographic occurrence of several ammonite species suggest they had undergone extensive planktic dispersal, thus ocean currents probably played an important role in their distributional patterns. Close