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• 11. [Article] Probabilistic Tsunami Hazard Assessment at Seaside, Oregon, for Near- and Far-Field Seismic Sources

  The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic ...

  Citation × Citation Citation Abstract Copy Title: Probabilistic Tsunami Hazard Assessment at Seaside, Oregon, for Near- and Far-Field Seismic Sources Author: González, Frank, Geist, Eric L., Jaffe, Bruce, Kânoğlu, Utku, Mofjeld, Harold O., Synolakis, Costas, Titov, Vasily V., Arcas, Diego Rodriguez, Bellomo, Douglas, Carlton, David, Horning, Thomas, Johnson, Jeff, Newman, Jean, Parsons, Thomas, Peters, Robert, Peterson, Curt D., Priest, George, Venturato, Angie, Weber, Joseph, Wong, Florence L., Yalçıner, Ahmet Year: 2009 The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100-year tsunami is generated most frequently by far-field sources in the Alaska-Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500-year tsunami is dominated by local sources in the Cascadia Subduction Zone and is characterized by maximum amplitudes in excess of 10 m and an inland extent of more than 1 km. The primary sources of uncertainty in these results include those associated with interevent time estimates, modeling of background sea level, and accounting for temporal changes in bathymetry and topography. Nonetheless, PTHA represents an important contribution to tsunami hazard assessment techniques; viewed in the broader context of risk analysis, PTHA provides a method for quantifying estimates of the likelihood and severity of the tsunami hazard, which can then be combined with vulnerability and exposure to yield estimates of tsunami risk. Title: Probabilistic Tsunami Hazard Assessment at Seaside, Oregon, for Near- and Far-Field Seismic Sources Author: González, Frank, Geist, Eric L., Jaffe, Bruce, Kânoğlu, Utku, Mofjeld, Harold O., Synolakis, Costas, Titov, Vasily V., Arcas, Diego Rodriguez, Bellomo, Douglas, Carlton, David, Horning, Thomas, Johnson, Jeff, Newman, Jean, Parsons, Thomas, Peters, Robert, Peterson, Curt D., Priest, George, Venturato, Angie, Weber, Joseph, Wong, Florence L., Yalçıner, Ahmet Year: 2009 The first probabilistic tsunami flooding maps have been developed. The methodology, called probabilistic tsunami hazard assessment (PTHA), integrates tsunami inundation modeling with methods of probabilistic seismic hazard assessment (PSHA). Application of the methodology to Seaside, Oregon, has yielded estimates of the spatial distribution of 100- and 500-year maximum tsunami amplitudes, i.e., amplitudes with 1% and 0.2% annual probability of exceedance. The 100-year tsunami is generated most frequently by far-field sources in the Alaska-Aleutian Subduction Zone and is characterized by maximum amplitudes that do not exceed 4 m, with an inland extent of less than 500 m. In contrast, the 500-year tsunami is dominated by local sources in the Cascadia Subduction Zone and is characterized by maximum amplitudes in excess of 10 m and an inland extent of more than 1 km. The primary sources of uncertainty in these results include those associated with interevent time estimates, modeling of background sea level, and accounting for temporal changes in bathymetry and topography. Nonetheless, PTHA represents an important contribution to tsunami hazard assessment techniques; viewed in the broader context of risk analysis, PTHA provides a method for quantifying estimates of the likelihood and severity of the tsunami hazard, which can then be combined with vulnerability and exposure to yield estimates of tsunami risk. Close

• 12. [Article] High-Resolution Ground-Penetrating Radar Profiles of Perennial Lake Ice in the McMurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, and Subbottom

  Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general ...

  Citation × Citation Citation Abstract Copy Title: High-Resolution Ground-Penetrating Radar Profiles of Perennial Lake Ice in the McMurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, and Subbottom Author: Dugan, Hilary A., Arcone, Steven A., Obryk, Maciej K., Doran, Peter T. Year: 2016 Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general interest in deeper stratigraphy and the difficulty of extensive profiling over rough snow surfaces. Our goal was to find further information on the origin of the deposition and formation of intra-ice layers, bottom topography, and subbottom deposits using GPR with pulses centered near 850 MHz on two permanently ice-covered lakes in the Mc- Murdo Dry Valleys, Antarctica. The profiles were obtained using a one-person sled operation over Lake Bonney, which is typical of lakes in the region, having an ice thickness that ranges between 3 and 5 m, and Lake Vida, where the maximum ice depth is at least 27 m. Lake Bonney exhibits a semicontinuous sediment horizon at approximately a 2-m depth and several minor horizons. In contrast, Lake Vida contains unconformably eroded and folded continuous reflection horizons, packages of minor horizons between major horizons, evidence of incised fluvial deposition along the bottom, and subbottom penetration of at least 4.5 m in some areas. Where the ice thickness is less than 20 m, the lake is frozen to the bottom. Most horizon waveform phase attributes indicate relatively lower permittivity than in the surrounding matrix. Consequently, we interpreted these strata to be caused by layers of pure ice embedded within a salty and dirty ice matrix, which were formed during minor flooding. These findings supported previous conclusions that Lake Vida ice formed from surface runoff in combination with periods of ablation. Title: High-Resolution Ground-Penetrating Radar Profiles of Perennial Lake Ice in the McMurdo Dry Valleys, Antarctica: Horizon Attributes, Unconformities, and Subbottom Author: Dugan, Hilary A., Arcone, Steven A., Obryk, Maciej K., Doran, Peter T. Year: 2016 Ground-penetrating radar (GPR) is not commonly used to study lake ice, and in general, the ground-based use of radar frequencies greater than 500 MHz in cryosphere geophysics is rare, due to a general interest in deeper stratigraphy and the difficulty of extensive profiling over rough snow surfaces. Our goal was to find further information on the origin of the deposition and formation of intra-ice layers, bottom topography, and subbottom deposits using GPR with pulses centered near 850 MHz on two permanently ice-covered lakes in the Mc- Murdo Dry Valleys, Antarctica. The profiles were obtained using a one-person sled operation over Lake Bonney, which is typical of lakes in the region, having an ice thickness that ranges between 3 and 5 m, and Lake Vida, where the maximum ice depth is at least 27 m. Lake Bonney exhibits a semicontinuous sediment horizon at approximately a 2-m depth and several minor horizons. In contrast, Lake Vida contains unconformably eroded and folded continuous reflection horizons, packages of minor horizons between major horizons, evidence of incised fluvial deposition along the bottom, and subbottom penetration of at least 4.5 m in some areas. Where the ice thickness is less than 20 m, the lake is frozen to the bottom. Most horizon waveform phase attributes indicate relatively lower permittivity than in the surrounding matrix. Consequently, we interpreted these strata to be caused by layers of pure ice embedded within a salty and dirty ice matrix, which were formed during minor flooding. These findings supported previous conclusions that Lake Vida ice formed from surface runoff in combination with periods of ablation. Close

• 13. [Article] Temporal and Crustal Effects on Differentiation of Tholeiite to Calcalkaline and Ferro-trachytic Suites, High Lava Plains, Oregon, USA

  Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of ...

  Citation × Citation Citation Abstract Copy Title: Temporal and Crustal Effects on Differentiation of Tholeiite to Calcalkaline and Ferro-trachytic Suites, High Lava Plains, Oregon, USA Author: Streck, Martin J., Grunder, Anita L. Year: 2012 Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of volcanism recorded in the central High Lava Plains, in western Harney Basin, three distinct mafic magmatic trends originate from primitive high-alumina olivine tholeiites (HAOT); they are tholeiitic, calcalkaline and ferro-trachytic. Tholeiitic basalts occur throughout the history and their compositions are derived by crystal fractionation while traversing the crust and mixing with evolved mafic magmas. Scavenging of apatite from crustal rocks and minor contamination with felsic melts accounts for P, incompatible element enrichments and increasing tilts of incompatible element patterns with differentiation. The calcalkaline mafic suite occurs in temporal association with abundant silicic volcanism and is the only suite with Fe decreasing with Mg. Calcalkaline compositions are derived from evolved tholeiitic basalt by crystal fractionation coupled with assimilation of felsic crust or crustal melts. The ferro-trachytic suite occurs mainly late, is highly enriched in incompatible element with patterns parallel to tholeiites from which it is derived by protracted fractionation and recharge. The three suites primarily reflect changes in magma flux and crustal interactions in time. High magma flux promotes crustal melting and contamination of tholeiite to make the calcalkaline suite. On the other hand, ferrotrachytic magmas erupted mainly late in the sequence, during magmatic waning and after significant basaltification of the crust. Title: Temporal and Crustal Effects on Differentiation of Tholeiite to Calcalkaline and Ferro-trachytic Suites, High Lava Plains, Oregon, USA Author: Streck, Martin J., Grunder, Anita L. Year: 2012 Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of volcanism recorded in the central High Lava Plains, in western Harney Basin, three distinct mafic magmatic trends originate from primitive high-alumina olivine tholeiites (HAOT); they are tholeiitic, calcalkaline and ferro-trachytic. Tholeiitic basalts occur throughout the history and their compositions are derived by crystal fractionation while traversing the crust and mixing with evolved mafic magmas. Scavenging of apatite from crustal rocks and minor contamination with felsic melts accounts for P, incompatible element enrichments and increasing tilts of incompatible element patterns with differentiation. The calcalkaline mafic suite occurs in temporal association with abundant silicic volcanism and is the only suite with Fe decreasing with Mg. Calcalkaline compositions are derived from evolved tholeiitic basalt by crystal fractionation coupled with assimilation of felsic crust or crustal melts. The ferro-trachytic suite occurs mainly late, is highly enriched in incompatible element with patterns parallel to tholeiites from which it is derived by protracted fractionation and recharge. The three suites primarily reflect changes in magma flux and crustal interactions in time. High magma flux promotes crustal melting and contamination of tholeiite to make the calcalkaline suite. On the other hand, ferrotrachytic magmas erupted mainly late in the sequence, during magmatic waning and after significant basaltification of the crust. Close

• 14. [Article] Establishing the Inundation Distance and Overtopping Height of Paleotsunami from the Late-Holocene Geologic Record at Open-Coastal Wetland Sites, Central Cascadia Margin

  Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone ...

  Citation × Citation Citation Abstract Copy Title: Establishing the Inundation Distance and Overtopping Height of Paleotsunami from the Late-Holocene Geologic Record at Open-Coastal Wetland Sites, Central Cascadia Margin Author: Schlichting, Robert B. Year: 2000 Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone earthquakes in the central Cascadia margin. Cascadia tsunami deposits have been reported for many coseismic subsidence events in bay marsh settings where tidal-channel features focus tsunami energy. Variable magnitude (8.5±0.5 Mw), frequency (500±300 yr recurrence), and rupture geometry produce widely varying computer model outcomes for Casdcadia tsunami inundation. The results presented in this thesis provide specific quantitative data regarding tsunami inundation at the open coast. Anomalous sand sheets that have been characterized consist of well-sorted beach sand that fine up-section. The thickness of the deposits vary from 45 em to 0.2 em, and thin in the landward direction. Many of the sand layers include detrital caps. One to three detritus and mud lamina are intra-layered in the deposits. Marine diatoms and bromine, a marine tracer, increase in concentration at each of the sand layers. Title: Establishing the Inundation Distance and Overtopping Height of Paleotsunami from the Late-Holocene Geologic Record at Open-Coastal Wetland Sites, Central Cascadia Margin Author: Schlichting, Robert B. Year: 2000 Mapping and stratigraphic investigations of back barrier, open-coastal plain sites have been used to establish minimum inundation distances and wave heights of tsunami produced by great subduction zone earthquakes in the central Cascadia margin. Cascadia tsunami deposits have been reported for many coseismic subsidence events in bay marsh settings where tidal-channel features focus tsunami energy. Variable magnitude (8.5±0.5 Mw), frequency (500±300 yr recurrence), and rupture geometry produce widely varying computer model outcomes for Casdcadia tsunami inundation. The results presented in this thesis provide specific quantitative data regarding tsunami inundation at the open coast. Anomalous sand sheets that have been characterized consist of well-sorted beach sand that fine up-section. The thickness of the deposits vary from 45 em to 0.2 em, and thin in the landward direction. Many of the sand layers include detrital caps. One to three detritus and mud lamina are intra-layered in the deposits. Marine diatoms and bromine, a marine tracer, increase in concentration at each of the sand layers. Close

• 15. [Article] Decadal Ecosystem Response to an Anomalous Melt Season in a Polar Desert in Antarctica

  Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem ...

  Citation × Citation Citation Abstract Copy Title: Decadal Ecosystem Response to an Anomalous Melt Season in a Polar Desert in Antarctica Author: Gooseff, Michael N., Barrett, John E., Adams, Byron J., Doran, Peter T., Fountain, Andrew J., Lyons, W. Berry, McKnight, Diana M., Priscu, John C., Sokol, Eric R., Takacs-Vesbach, Cristina, Vandegehuchte, Martijn L., Virginia, Ross A., Wall, Diana H. Year: 2017 Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt (‘flood year’)—a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties. Title: Decadal Ecosystem Response to an Anomalous Melt Season in a Polar Desert in Antarctica Author: Gooseff, Michael N., Barrett, John E., Adams, Byron J., Doran, Peter T., Fountain, Andrew J., Lyons, W. Berry, McKnight, Diana M., Priscu, John C., Sokol, Eric R., Takacs-Vesbach, Cristina, Vandegehuchte, Martijn L., Virginia, Ross A., Wall, Diana H. Year: 2017 Amplified climate change in polar regions is significantly altering regional ecosystems, yet there are few long-term records documenting these responses. The McMurdo Dry Valleys (MDV) cold desert ecosystem is the largest ice-free area of Antarctica, comprising soils, glaciers, meltwater streams and permanently ice-covered lakes. Multi-decadal records indicate that the MDV exhibited a distinct ecosystem response to an uncharacteristic austral summer and ensuing climatic shift. A decadal summer cooling phase ended in 2002 with intense glacial melt (‘flood year’)—a step-change in water availability triggering distinct changes in the ecosystem. Before 2002, the ecosystem exhibited synchronous behaviour: declining stream flow, decreasing lake levels, thickening lake ice cover, decreasing primary production in lakes and streams, and diminishing soil secondary production. Since 2002, summer air temperatures and solar flux have been relatively consistent, leading to lake level rise, lake ice thinning and elevated stream flow. Biological responses varied; one stream cyanobacterial mat type immediately increased production, but another stream mat type, soil invertebrates and lake primary productivity responded asynchronously a few years after 2002. This ecosystem response to a climatic anomaly demonstrates differential biological community responses to substantial perturbations, and the mediation of biological responses to climate change by changes in physical ecosystem properties. Close

• 16. [Article] A Tectonic Study of a Part of the Northern Eagle Cap Wilderness Area, Northeastern Oregon

  Upper Triassic metavolcanic and metasedimentary strata in the study area are intruded by the Hurricane Divide and Craig Mountain Plutons of the Late Jurassic-Cretaceous Wallowa Batholith. The Clover Creek ...

  Citation × Citation Citation Abstract Copy Title: A Tectonic Study of a Part of the Northern Eagle Cap Wilderness Area, Northeastern Oregon Author: Neal, Kenneth Gordon Year: 1973 Upper Triassic metavolcanic and metasedimentary strata in the study area are intruded by the Hurricane Divide and Craig Mountain Plutons of the Late Jurassic-Cretaceous Wallowa Batholith. The Clover Creek Greenstone is overlain by the Martin Bridge Limestone, which is in tum overlain by the Hurwal Argillite; although the sequence is in normal stratigraphic order, contacts are generally tectonic. Concurrent with Early-Middle Jurassic regional deformation, during intermediate to mafic dikes, emplacement of the plutons of the Wallowa Batholith began. The plutons intruded vertically through the greenstone and limestone and then horizontally above the greenstone. This resulted in intense penetrative plastic deformation particularly of the Martin Bridge Limestone. Emplacement of the Hurricane Divide Pluton followed a northeast axis, and resulted in isoclinal folding and the formation of northerly trending synformal anticlines in the Martin Bridge atop a zone of uncoupling between the plastic limestone and the more rigid underlying Clover Creek metavolcanic basement. Subsequent final emplacement of the Craig Mountain Pluton caused cross folding of these anticlinal structures. Granitic plutonism was followed by regional uplift with associated faulting and erosion. Miocene Columbia River Basalt flood lavas were injected along many of the more northerly trending of these faults. This magmatism was concurrent with or followed by block uplift on the order of 1800 m of the Wallowa Mountains along the Wallowa Fault. Title: A Tectonic Study of a Part of the Northern Eagle Cap Wilderness Area, Northeastern Oregon Author: Neal, Kenneth Gordon Year: 1973 Upper Triassic metavolcanic and metasedimentary strata in the study area are intruded by the Hurricane Divide and Craig Mountain Plutons of the Late Jurassic-Cretaceous Wallowa Batholith. The Clover Creek Greenstone is overlain by the Martin Bridge Limestone, which is in tum overlain by the Hurwal Argillite; although the sequence is in normal stratigraphic order, contacts are generally tectonic. Concurrent with Early-Middle Jurassic regional deformation, during intermediate to mafic dikes, emplacement of the plutons of the Wallowa Batholith began. The plutons intruded vertically through the greenstone and limestone and then horizontally above the greenstone. This resulted in intense penetrative plastic deformation particularly of the Martin Bridge Limestone. Emplacement of the Hurricane Divide Pluton followed a northeast axis, and resulted in isoclinal folding and the formation of northerly trending synformal anticlines in the Martin Bridge atop a zone of uncoupling between the plastic limestone and the more rigid underlying Clover Creek metavolcanic basement. Subsequent final emplacement of the Craig Mountain Pluton caused cross folding of these anticlinal structures. Granitic plutonism was followed by regional uplift with associated faulting and erosion. Miocene Columbia River Basalt flood lavas were injected along many of the more northerly trending of these faults. This magmatism was concurrent with or followed by block uplift on the order of 1800 m of the Wallowa Mountains along the Wallowa Fault. Close

• 17. [Article] Defining the Terroir of the Columbia Gorge Wine Region, Oregon and Washington, USA Using Geographic Information Systems (GIS)

  The Columbia Gorge Wine Region (CGWR) is an emerging wine producing area that extends for about 100km along the Columbia River in Oregon and Washington State in which the number of vineyards, wineries ...

  Citation × Citation Citation Abstract Copy Title: Defining the Terroir of the Columbia Gorge Wine Region, Oregon and Washington, USA Using Geographic Information Systems (GIS) Author: Whitney, Hilary Year: 2015 The Columbia Gorge Wine Region (CGWR) is an emerging wine producing area that extends for about 100km along the Columbia River in Oregon and Washington State in which the number of vineyards, wineries and physical terroir conditions have yet to be defined. To better understand the physical factors affecting Oregon and Washington wine, this project analyzes climate, topography, geology and soil at vineyards in the CGWR. This was accomplished using Geographic Information Systems, existing earth science databases and field work. The region, which includes the Columbia Gorge American Viticulture Area (AVA) and the southwest portion of the Columbia Valley AVA, is home to 82 vineyards, 513 hectares (1268 acres), 37 wineries and 41 different varieties of Vitus Vinifera. Vineyards range in elevation from 29 to 548 meters (95 to 1799 feet). Vintner responses to a grower's survey suggest that twenty-eight grape varieties account for 98% of the estimated grape variety acreage, with Pinot Noir being the most widely planted grape variety in both AVAs. The boundaries of each climatic regime were mapped based on 1981-2010 PRISM data, the Winkler Index (Amerine and Winkler, 1944) updated by Jones et al. (2010) and climatic maturity groupings designed for Oregon (Jones et al., 2002; Jones et al., 2010). Three Winkler climate regimes are represented within the CGWR, including regions Ia, Ib, and II from the Winkler Index (Jones et al., 2010). The diversity in regimes allows for a diversity of grape varieties to be planted within the regime. The average growing season temperatures and growing degree days, respectively, from 1981-2010 calculated for vineyards ranges from 13.7°C (55.7°F) to 17.7°C (63.9°F) and 871 for °C (1567 for °F) to 1664 for °C (2994 for °F) respectively. 58% of the vineyards are characterized in an intermediate climatic regime, 29% are within a cool climatic regime, 9% are within a warm climatic regime and 4% are on the boundaries between a cool, intermediate or warm regime. 80% of the vineyards are within Regions Ia and Ib characterized by the Winkler Index, and 20% are within Region II. The growing degrees days calculated for the CGWR are similar those measured in the Willamette Valley, Oregon, Burgundy, France, Umpqua Valley AVA in Oregon and Bordeaux wine region in France. All of the soils currently being used to grow grapes are well-drained and within a xeric moisture regime, which are favorable conditions for viticulture. 30 soil series are represented among the vineyard sites, with the Chemawa Series (Underwood Mountain) and Walla Walla Series (eastern portions) being the dominant soil series used to grow grapes. Majority of the soils contain a silt loam texture. Soil Survey data for Oregon and Washington suggest that loess is extensive in the CGWR, with 46.5% of the total vineyard acreage planted on soils formed in loess. The Missoula Floods also greatly influenced the texture and age of the soil in this region, with skeletal textures being close to the Columbia River. Other common geological deposits at vineyards in the CGWR include, Quaternary Basalt (19.6%), Missoula Flood deposits (9.1%), The Dalles Formation (8.0%), Columbia River Basalt Group (7.5%), Pliocene Basalt (3.0%), Quaternary Surficial deposits (3.0%), lahars (2.3%) and Quaternary Basaltic Andesite and Andesite (0.9%). Common geological deposits, soil series, and climate conditions at vineyard sites vary spatially in the region, and therefore it is suggested that future work focus on separating the region into separate climatic sub-AVA regimes to better reflect the diversity in terroir conditions. Title: Defining the Terroir of the Columbia Gorge Wine Region, Oregon and Washington, USA Using Geographic Information Systems (GIS) Author: Whitney, Hilary Year: 2015 The Columbia Gorge Wine Region (CGWR) is an emerging wine producing area that extends for about 100km along the Columbia River in Oregon and Washington State in which the number of vineyards, wineries and physical terroir conditions have yet to be defined. To better understand the physical factors affecting Oregon and Washington wine, this project analyzes climate, topography, geology and soil at vineyards in the CGWR. This was accomplished using Geographic Information Systems, existing earth science databases and field work. The region, which includes the Columbia Gorge American Viticulture Area (AVA) and the southwest portion of the Columbia Valley AVA, is home to 82 vineyards, 513 hectares (1268 acres), 37 wineries and 41 different varieties of Vitus Vinifera. Vineyards range in elevation from 29 to 548 meters (95 to 1799 feet). Vintner responses to a grower's survey suggest that twenty-eight grape varieties account for 98% of the estimated grape variety acreage, with Pinot Noir being the most widely planted grape variety in both AVAs. The boundaries of each climatic regime were mapped based on 1981-2010 PRISM data, the Winkler Index (Amerine and Winkler, 1944) updated by Jones et al. (2010) and climatic maturity groupings designed for Oregon (Jones et al., 2002; Jones et al., 2010). Three Winkler climate regimes are represented within the CGWR, including regions Ia, Ib, and II from the Winkler Index (Jones et al., 2010). The diversity in regimes allows for a diversity of grape varieties to be planted within the regime. The average growing season temperatures and growing degree days, respectively, from 1981-2010 calculated for vineyards ranges from 13.7°C (55.7°F) to 17.7°C (63.9°F) and 871 for °C (1567 for °F) to 1664 for °C (2994 for °F) respectively. 58% of the vineyards are characterized in an intermediate climatic regime, 29% are within a cool climatic regime, 9% are within a warm climatic regime and 4% are on the boundaries between a cool, intermediate or warm regime. 80% of the vineyards are within Regions Ia and Ib characterized by the Winkler Index, and 20% are within Region II. The growing degrees days calculated for the CGWR are similar those measured in the Willamette Valley, Oregon, Burgundy, France, Umpqua Valley AVA in Oregon and Bordeaux wine region in France. All of the soils currently being used to grow grapes are well-drained and within a xeric moisture regime, which are favorable conditions for viticulture. 30 soil series are represented among the vineyard sites, with the Chemawa Series (Underwood Mountain) and Walla Walla Series (eastern portions) being the dominant soil series used to grow grapes. Majority of the soils contain a silt loam texture. Soil Survey data for Oregon and Washington suggest that loess is extensive in the CGWR, with 46.5% of the total vineyard acreage planted on soils formed in loess. The Missoula Floods also greatly influenced the texture and age of the soil in this region, with skeletal textures being close to the Columbia River. Other common geological deposits at vineyards in the CGWR include, Quaternary Basalt (19.6%), Missoula Flood deposits (9.1%), The Dalles Formation (8.0%), Columbia River Basalt Group (7.5%), Pliocene Basalt (3.0%), Quaternary Surficial deposits (3.0%), lahars (2.3%) and Quaternary Basaltic Andesite and Andesite (0.9%). Common geological deposits, soil series, and climate conditions at vineyard sites vary spatially in the region, and therefore it is suggested that future work focus on separating the region into separate climatic sub-AVA regimes to better reflect the diversity in terroir conditions. Close

• 18. [Article] Field Geology and Petrologic Investigation of the Strawberry Volcanics, Northeast Oregon

  The Strawberry Volcanics of Northeast Oregon are a group of geochemically related lavas with a diverse chemical range (basalt to rhyolite) that erupted between 16.2 and 12.5 Ma and co-erupted with the ...

  Citation × Citation Citation Abstract Copy Title: Field Geology and Petrologic Investigation of the Strawberry Volcanics, Northeast Oregon Author: Steiner, Arron Richard Year: 2016 The Strawberry Volcanics of Northeast Oregon are a group of geochemically related lavas with a diverse chemical range (basalt to rhyolite) that erupted between 16.2 and 12.5 Ma and co-erupted with the large, (~200,000 km3) Middle Miocene tholeiitic lavas of the Columbia River Basalt Group (CRBG), which erupted near and geographically surround the Strawberry Volcanics. The rhyolitic lavas of the Strawberry Volcanics produced the oldest 40Ar/39Ar ages measured in this study with ages ranging from 16.2 Ma to 14.6 Ma, and have an estimated total erupted volume of 100 km3. The mafic and intermediate lavas of the Strawberry Volcanics include both tholeiitic and calc-alkaline compositions; calc-alkaline andesite is the dominant type by volume. 40Ar/39Ar ages of the mafic and intermediate lava flows range from 15.6 Ma to 12.5 Ma, and volume estimates of the intermediate lavas are approximately 1,100 km3. The magmas that gave rise to the Strawberry Volcanics traveled to the surface through numerous dikes, some of which have been exposed at the surface and supplied lava to fissure – style eruptions and/or shield volcanoes. Herein, we show that the Strawberry Volcanics are related to the CRBG in both time and space and share a chemical affinity, specifically to the Steens Basalt. Chemical similarities are observed in normalized trace element patterns, selected trace element ratios, and radiogenic isotopes. Comparison of the Strawberry Volcanic rhyolites to the other Middle Miocene rhyolites of eastern Oregon associated with the initiation of the Yellowstone – Snake River mantle plume reveals similar eruption ages, trace element compositions, including the rare earth elements (REEs), and "A-type" rhyolite characteristics. These data suggest that the Strawberry Volcanics are part of the regional volcanism (basalt to rhyolite) of the Columbia River Basalt Province. The petrogenesis of the Strawberry Volcanics can be explained as follows: 1) The tholeiitic, intermediate magmas were produced by fractional crystallization of mafic magmas, which have a commonality with the surrounding Columbia River Basalt Group; 2) The calc-alkaline magmas are a result of mixing between tholeiitic basalt, rhyolite, and crust. The arc-like signature of the calc-alkaline lavas (elevated large ion lithophiles) is a result of both the melting source region and the end-members with which the mafic magmas mixed/contaminated. Other authors have produced similar findings from within the Basin and Range/Oregon-Idaho graben and CRB province. The difference at the Strawberry Volcanics is that there is no need for a primitive calc-alkaline magma or extensive fractional crystallization to generate the calc-alkaline andesites. Alternatively, the calc-alkaline magmas of the Strawberry Volcanics were generated by a more primitive tholeiitic magma than erupted at the surface, which interacted with crustal melts and assimilated crustal lithologies from the complex zone of assimilated terranes that make up the basement of eastern Oregon. Title: Field Geology and Petrologic Investigation of the Strawberry Volcanics, Northeast Oregon Author: Steiner, Arron Richard Year: 2016 The Strawberry Volcanics of Northeast Oregon are a group of geochemically related lavas with a diverse chemical range (basalt to rhyolite) that erupted between 16.2 and 12.5 Ma and co-erupted with the large, (~200,000 km3) Middle Miocene tholeiitic lavas of the Columbia River Basalt Group (CRBG), which erupted near and geographically surround the Strawberry Volcanics. The rhyolitic lavas of the Strawberry Volcanics produced the oldest 40Ar/39Ar ages measured in this study with ages ranging from 16.2 Ma to 14.6 Ma, and have an estimated total erupted volume of 100 km3. The mafic and intermediate lavas of the Strawberry Volcanics include both tholeiitic and calc-alkaline compositions; calc-alkaline andesite is the dominant type by volume. 40Ar/39Ar ages of the mafic and intermediate lava flows range from 15.6 Ma to 12.5 Ma, and volume estimates of the intermediate lavas are approximately 1,100 km3. The magmas that gave rise to the Strawberry Volcanics traveled to the surface through numerous dikes, some of which have been exposed at the surface and supplied lava to fissure – style eruptions and/or shield volcanoes. Herein, we show that the Strawberry Volcanics are related to the CRBG in both time and space and share a chemical affinity, specifically to the Steens Basalt. Chemical similarities are observed in normalized trace element patterns, selected trace element ratios, and radiogenic isotopes. Comparison of the Strawberry Volcanic rhyolites to the other Middle Miocene rhyolites of eastern Oregon associated with the initiation of the Yellowstone – Snake River mantle plume reveals similar eruption ages, trace element compositions, including the rare earth elements (REEs), and "A-type" rhyolite characteristics. These data suggest that the Strawberry Volcanics are part of the regional volcanism (basalt to rhyolite) of the Columbia River Basalt Province. The petrogenesis of the Strawberry Volcanics can be explained as follows: 1) The tholeiitic, intermediate magmas were produced by fractional crystallization of mafic magmas, which have a commonality with the surrounding Columbia River Basalt Group; 2) The calc-alkaline magmas are a result of mixing between tholeiitic basalt, rhyolite, and crust. The arc-like signature of the calc-alkaline lavas (elevated large ion lithophiles) is a result of both the melting source region and the end-members with which the mafic magmas mixed/contaminated. Other authors have produced similar findings from within the Basin and Range/Oregon-Idaho graben and CRB province. The difference at the Strawberry Volcanics is that there is no need for a primitive calc-alkaline magma or extensive fractional crystallization to generate the calc-alkaline andesites. Alternatively, the calc-alkaline magmas of the Strawberry Volcanics were generated by a more primitive tholeiitic magma than erupted at the surface, which interacted with crustal melts and assimilated crustal lithologies from the complex zone of assimilated terranes that make up the basement of eastern Oregon. Close

• 19. [Article] Large-Scale Fluidization Features from Late Holocene Coseismic Paleoliquefaction in the Willamette River Forearc Valley, Central Cascadia Subduction Zone, Oregon, USA

  A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in ...

  Citation × Citation Citation Abstract Copy Title: Large-Scale Fluidization Features from Late Holocene Coseismic Paleoliquefaction in the Willamette River Forearc Valley, Central Cascadia Subduction Zone, Oregon, USA Author: Peterson, Curt D., Kristensen, Kurt, Minor, Rick Year: 2014 A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. Eight cutbank sites are reported that show evidence of large-scale fluidization features (≥10 cm width) including clastic sand dikes and intruded sand sills in Holocene overbank mud deposits. The targeted alluvial sequences, and hosted paleoliquefaction records, are of late Holocene age, as based on radiocarbon dating, flood silt thickness (≤4 m thickness), and minimal consolidation of dike sand (~1.5 ± 0.5 kg·cm-2 unconfined compressive strength). Two of the paleoliquefaction sites, which are separated by 150 km distance, overlap in age (175 - 500 yr BP) with the last great megathrust rupture (Mw 8.5 - 9.0) in the Cascadia margin, dated at AD 1700. The scarcity of exposed late Holocene paleoliquefaction sites in the Willamette River cutbanks motivated subsurface searches for thick basal sand deposits and overlying fluidization features, using floodplain geomorphological analyses, ground penetrating radar, and remote pole-camera scans of deep trench walls (3 - 4 m depth). The onset of large-scale fluidization features occurred in overbank mud deposits (2 - 3 m thickness) above unconsolidated sand bodies (≥2 m thickness) with unconfined compressive strengths of ~1.5 ± 0.5 kg·cm-2. We recommend geomorphically-targeted subsurface explorations rather than traditional cutbank searches for evidence of coseismic paleoliquefaction in high-gradient river valley systems. Title: Large-Scale Fluidization Features from Late Holocene Coseismic Paleoliquefaction in the Willamette River Forearc Valley, Central Cascadia Subduction Zone, Oregon, USA Author: Peterson, Curt D., Kristensen, Kurt, Minor, Rick Year: 2014 A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. A search of Willamette River cutbanks was conducted for the presence of late Holocene paleoli-quefaction records in the Willamette forearc valley, located 175 ± 25 km landward from the buried trench in the central Cascadia subduction zone. Eight cutbank sites are reported that show evidence of large-scale fluidization features (≥10 cm width) including clastic sand dikes and intruded sand sills in Holocene overbank mud deposits. The targeted alluvial sequences, and hosted paleoliquefaction records, are of late Holocene age, as based on radiocarbon dating, flood silt thickness (≤4 m thickness), and minimal consolidation of dike sand (~1.5 ± 0.5 kg·cm-2 unconfined compressive strength). Two of the paleoliquefaction sites, which are separated by 150 km distance, overlap in age (175 - 500 yr BP) with the last great megathrust rupture (Mw 8.5 - 9.0) in the Cascadia margin, dated at AD 1700. The scarcity of exposed late Holocene paleoliquefaction sites in the Willamette River cutbanks motivated subsurface searches for thick basal sand deposits and overlying fluidization features, using floodplain geomorphological analyses, ground penetrating radar, and remote pole-camera scans of deep trench walls (3 - 4 m depth). The onset of large-scale fluidization features occurred in overbank mud deposits (2 - 3 m thickness) above unconsolidated sand bodies (≥2 m thickness) with unconfined compressive strengths of ~1.5 ± 0.5 kg·cm-2. We recommend geomorphically-targeted subsurface explorations rather than traditional cutbank searches for evidence of coseismic paleoliquefaction in high-gradient river valley systems. Close