Ralph Shroba
Ralph Shroba is a Scientist Emeritus with the Geosciences and Environmental Change Science Center
Science and Products
Data Release for Geologic Map of Petroglyph National Monument and Vicinity, Bernalillo County, New Mexico
This geologic map depicts and briefly describes geologic units underlying Petroglyph National Monument and immediately adjacent areas in Bernalillo County, New Mexico. The Monument is underlain dominantly by Quaternary basalts of the Albuquerque Volcanoes volcanic field, a series of basin-filling volcanic flows and associated vents from a monogenetic volcanic highland along the eastern margin of t
Data Release for Geologic Map of the Fort Collins 30' x 60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming
This geologic map provides new and compiled geologic mapping at 1:100,000-scale in the Fort Collins 30' x 60' quadrangle covering the northern Front Range and adjacent areas of Colorado.
Data release of geospatial map database, argon geochronology and geochemistry data for: Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
This dataset accompanies publication "Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado". Data presented here include the digital geologic database, 40Ar/39Ar geochronology and major and trace element chemistry from lava flows and an ignimbrite. The geologic database includes spatial feature classes and non-spatial tables that collectively contain the geologi
Data release of Geologic Map of the Upper Arkansas River Valley Region, North-Central, Colorado
This 1:50,000-scale geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley, between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This work also incorporates new detailed geologic ma
Filter Total Items: 20
Geologic map of Petroglyph National Monument and vicinity, Bernalillo County, New Mexico
This geologic map depicts and briefly describes geologic units underlying Petroglyph National Monument and immediately adjacent areas in Bernalillo County, New Mexico. The Monument is underlain dominantly by Quaternary basalts of the Albuquerque Volcanoes volcanic field, a series of basin-filling volcanic flows and associated vents from a monogenetic volcanic highland along the eastern margin of t
Geologic map of the Fort Collins 30'×60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming
The rocks and landforms of the Fort Collins 30′ × 60′ 1:100,000-scale U.S. Geological Survey quadrangle reveals a particularly complete record of geologic history in the northern Front Range of Colorado. The Proterozoic basement rocks exposed in the core of the range preserve evidence of Paleoproterozoic marine sedimentation, volcanism, and regional soft-sediment deformation, followed by regional
Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
The geologic map of the San Antonio Mountain area in northern New Mexico and southern Colorado is located along the west-central part of the San Luis Valley. The San Luis Valley is the geomorphic expression of the San Luis Basin, an extensional basin associated with the northern Rio Grande rift. Deposits within the map area record volcanic, sedimentary, and tectonic processes over the last ~33 mil
Geologic map of the upper Arkansas River valley region, north-central Colorado
This 1:50,000-scale U.S. Geological Survey geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This report also incorporates
Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado
The Alamosa 30'× 60' quadrangle is located in the central San Luis Basin of southern Colorado and is bisected by the Rio Grande. The Rio Grande has headwaters in the San Juan Mountains of Colorado and ultimately discharges into the Gulf of Mexico 3,000 kilometers (km) downstream. Alluvial floodplains and associated deposits of the Rio Grande and east-draining tributaries, La Jara Creek and Conejos
Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado
The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by young
Geologic map of the Ute Mountain 7.5' quadrangle, Taos County, New Mexico, and Conejos and Costilla Counties, Colorado
The Ute Mountain 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Ute Mountain has the distinction of being one of the largest intermediate composition eruptive center
Geologic map of the Sunshine 7.5' quadrangle, Taos County, New Mexico
The Sunshine 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Sunshine Valley, named for the small locale of Sunshine, is incised by a series of northeast-trending dra
Geologic map of the Bailey 30' x 60' quadrangle, North-Central Colorado
The Bailey, Colo. 1:100,000-scale quadrangle lies within two physiographic and geologic provinces in central Colorado: 1) the Front Range and 2) South Park. Most of the Front Range is composed of Proterozoic rocks ranging in age from 1,790 Ma to 1,074 Ma. Along the eastern flanks and within the Denver Basin, sedimentary rocks ranging from Pennsylvanian to Cretaceous are deformed and steeply tilted
Geologic map of the Montoso Peak quadrangle, Santa Fe and Sandoval Counties, New Mexico
The Montoso Peak quadrangle is underlain by volcanic rocks and associated sediments of the Cerros del Rio volcanic field in the southern part of the Española Basin that record volcanic, faulting, alluvial, colluvial, and eolian processes over the past three million years. The geology was mapped from 1997 to 1999 and modified in 2004 to 2008. The geologic mapping was carried out in support of the U
Geologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado
Recent mapping and geochronologic studies for the eastern half of the Vail 1:100,000-scale quadrangle have significantly improved our understanding of (1) Paleoproterozoic history of the basement rocks of the Gore Range and Williams Fork Mountains (western margin of the Front Range), (2) the Late Paleozoic history of the Gore fault system, (3) Laramide contractional tectonism, including deformatio
Geologic map of the Fraser 7.5-minute quadrangle, Grand County, Colorado
The geologic map of the Fraser quadrangle, Grand County, Colo., portrays the geology along the western boundary of the Front Range and the eastern part of the Fraser basin near the towns of Fraser and Winter Park. The oldest rocks in the quadrangle include gneiss, schist, and plutonic rocks of Paleoproterozoic age that are intruded by younger plutonic rocks of Mesoproterozoic age. These basement r
Filter Total Items: 14
Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado
Deposits of the North Park Formation of late Oligocene and Miocene age are locally exposed at small, widely spaced outcrops along the margins of the roughly northwest-trending North Park syncline in the southern part of North Park, a large intermontane topographic basin in Jackson County in north-central Colorado. These outcrops suggest that rocks and sediments of the North Park Formation consist
Authors
Ralph R. Shroba
Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains
This report describes, in a nontechnical style, the geologic history and mining activity in the Blue River region of Colorado, which includes all of Summit County. The geologic story begins with the formation of ancient basement rocks, as old as about 1700 million years, and continues with the deposition of sedimentary rocks on a vast erosional surface beginning in the Cambrian Period (about 530 m
Authors
Karl S. Kellogg, Bruce Bryant, Ralph R. Shroba
Pinedale glacial history of the upper Arkansas River valley: New moraine chronologies, modeling results, and geologic mapping
This field-trip guide outlines the glacial history of the upper Arkansas River valley, Colorado, and builds on a previous GSA field trip to the area in 2010. The following will be presented: (1) new cosmogenic 10Be exposure ages of moraine boulders from the Pinedale and Bull Lake glaciations (Marine Isotope Stages 2 and 6, respectively) located adjacent to the Twin Lakes Reservoir, (2) numerical m
Authors
Avriel D. Schweinsberg, Jason P. Briner, Ralph R. Shroba, Joseph M. Licciardi, Eric M. Leonard, Keith A. Brugger, Charles M. Russell
Preliminary geologic map of the Big Costilla Peak area, Taos County, New Mexico, and Costilla County, Colorado
This map covers the Big Costilla Peak, New Mex.‒Colo. quadrangle and adjacent parts of three other 7.5 minute quadrangles: Amalia, New Mex.‒Colo., Latir Peak, New Mex., and Comanche Point, New Mex. The study area is in the southwesternmost part of that segment of the Sangre de Cristo Mountains known as the Culebra Range; the Taos Range segment lies to the southwest of Costilla Creek and its tribut
Authors
Christopher J. Fridrich, Ralph R. Shroba, Adam M. Hudson
Beyond Colorado's Front Range - A new look at Laramide basin subsidence, sedimentation, and deformation in north-central Colorado
This field trip highlights recent research into the Laramide uplift, erosion, and sedimentation on the western side of the northern Colorado Front Range. The Laramide history of the North Park-Middle Park basin (designated the Colorado Headwaters Basin in this paper) is distinctly different from that of the Denver basin on the eastern flank of the range. The Denver basin stratigraphy records the t
Authors
James C. Cole, James H. Trexler, Patricia H. Cashman, Ian M. Miller, Ralph R. Shroba, Michael A. Cosca, Jeremiah B. Workman
Preliminary geologic map of the Vermejo Peak area, Colfax and Taos Counties, New Mexico and Las Animas and Costilla Counties, Colorado
This geologic map covers four 7.5-minute quadrangles-The Wall, NM-CO (New Mexico-Colorado), Vermejo Park, NM-CO, Ash Mountain, NM, and Van Bremmer Park, NM. The study area straddles the boundary between the eastern flank of the Sangre de Cristo Mountains and the western margin of the Raton Basin, with about two-thirds of the map area in the basin. The Raton Basin is a foreland basin that formed im
Authors
Christopher J. Fridrich, Ralph R. Shroba, Charles L. Pillmore, Adam M. Hudson
Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico
Results from luminescence dating on 13 samples from the Albuquerque area show that major-drainage fluvial deposits represent significant periods of aggradation that formed paired, correlatable terraces on the east and west margins of the Rio Grande valley . The youngest terrace fills (Primero Alto) formed during late Pleistocene as a result of streamflow variations with climate cooling during Mari
Authors
Shannon Mahan, Byron D. Stone, Ralph R. Shroba
The Rocky Mountain glacial model; the Wind River Range, Wyoming
No abstract available.
Authors
D. E. Dahms, R. D. Hall, Ralph R. Shroba, C. J. Sorenson, E. A. Lynch, M. T. Applegarth
Quaternary stratigraphy, geomorphology, soils, and alpine archaeology in an alpine-to-plains transect, Colorado Front Range
No abstract available.
Authors
David P. Dethier, James B. Benedict, Peter W. Birkeland, Nel Caine, P. Thompson Davis, Richard F. Madole, Penny E. Patterson, Alan B. Price, Taylor F. Schildgen, Ralph R. Shroba
Eagle collapse center: Interpretation of evidence for late Cenozoic evaporite-related deformation in the Eagle River basin, Colorado
Evaporite tectonism resulted in deformation and collapse over an area of ~2500 km2 that is referred to as the Eagle collapse center. The collapse center includes much of the Eagle and Colorado River drainage basins between Vail, Dotsero, and McCoy, Colorado. The volume loss of evaporitic rocks by dissolution in the collapse center is estimated to be nearly 1700 km33 . Before ca. 10 Ma, Miocene bas
Authors
David J. Lidke, Mark R. Hudson, R. B. Scott, Ralph R. Shroba, Michael J. Kunk, W. J. Perry, R. M. Kirkham, James R. Budahn, R. K. Streufert, J.O. Stanley, B.L. Widmann
Soil relative dating of moraine and outwash-terrace sequences in the northern part of the upper Arkansas Valley, central Colorado, U.S.A.
Profile development indices for soils developed in moraines and outwash near Twin Lakes and in outwash near Leadville support the correlation of moraines with subdued morphology and two high outwash terraces with the Bull Lake glaciation (ca. 130-160 ka) and the correlation of hummocky moraines and two low outwash terraces with the Pinedale glaciation (ca. 14-47 ka). Elsewhere in the northern part
Authors
Alan R. Nelson, Ralph R. Shroba
Preliminary geologic map of the Rifle Quadrangle, Garfield County, Colorado
No abstract available.
Authors
Ralph R. Shroba, M. W. Green, G. M. Fairer
Science and Products
Data Release for Geologic Map of Petroglyph National Monument and Vicinity, Bernalillo County, New Mexico
This geologic map depicts and briefly describes geologic units underlying Petroglyph National Monument and immediately adjacent areas in Bernalillo County, New Mexico. The Monument is underlain dominantly by Quaternary basalts of the Albuquerque Volcanoes volcanic field, a series of basin-filling volcanic flows and associated vents from a monogenetic volcanic highland along the eastern margin of t
Data Release for Geologic Map of the Fort Collins 30' x 60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming
This geologic map provides new and compiled geologic mapping at 1:100,000-scale in the Fort Collins 30' x 60' quadrangle covering the northern Front Range and adjacent areas of Colorado.
Data release of geospatial map database, argon geochronology and geochemistry data for: Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
This dataset accompanies publication "Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado". Data presented here include the digital geologic database, 40Ar/39Ar geochronology and major and trace element chemistry from lava flows and an ignimbrite. The geologic database includes spatial feature classes and non-spatial tables that collectively contain the geologi
Data release of Geologic Map of the Upper Arkansas River Valley Region, North-Central, Colorado
This 1:50,000-scale geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley, between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This work also incorporates new detailed geologic ma
Filter Total Items: 20
Geologic map of Petroglyph National Monument and vicinity, Bernalillo County, New Mexico
This geologic map depicts and briefly describes geologic units underlying Petroglyph National Monument and immediately adjacent areas in Bernalillo County, New Mexico. The Monument is underlain dominantly by Quaternary basalts of the Albuquerque Volcanoes volcanic field, a series of basin-filling volcanic flows and associated vents from a monogenetic volcanic highland along the eastern margin of t
Geologic map of the Fort Collins 30'×60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming
The rocks and landforms of the Fort Collins 30′ × 60′ 1:100,000-scale U.S. Geological Survey quadrangle reveals a particularly complete record of geologic history in the northern Front Range of Colorado. The Proterozoic basement rocks exposed in the core of the range preserve evidence of Paleoproterozoic marine sedimentation, volcanism, and regional soft-sediment deformation, followed by regional
Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado
The geologic map of the San Antonio Mountain area in northern New Mexico and southern Colorado is located along the west-central part of the San Luis Valley. The San Luis Valley is the geomorphic expression of the San Luis Basin, an extensional basin associated with the northern Rio Grande rift. Deposits within the map area record volcanic, sedimentary, and tectonic processes over the last ~33 mil
Geologic map of the upper Arkansas River valley region, north-central Colorado
This 1:50,000-scale U.S. Geological Survey geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This report also incorporates
Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado
The Alamosa 30'× 60' quadrangle is located in the central San Luis Basin of southern Colorado and is bisected by the Rio Grande. The Rio Grande has headwaters in the San Juan Mountains of Colorado and ultimately discharges into the Gulf of Mexico 3,000 kilometers (km) downstream. Alluvial floodplains and associated deposits of the Rio Grande and east-draining tributaries, La Jara Creek and Conejos
Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado
The geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado, portrays the geology in the upper Arkansas valley and along the lower flanks of the Sawatch Range and Mosquito Range near the town of Granite. The oldest rocks, exposed in the southern and eastern parts of the quadrangle, include gneiss and plutonic rocks of Paleoproterozoic age. These rocks are intruded by young
Geologic map of the Ute Mountain 7.5' quadrangle, Taos County, New Mexico, and Conejos and Costilla Counties, Colorado
The Ute Mountain 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Ute Mountain has the distinction of being one of the largest intermediate composition eruptive center
Geologic map of the Sunshine 7.5' quadrangle, Taos County, New Mexico
The Sunshine 7.5' quadrangle is located in the south-central part of the San Luis Basin of northern New Mexico, in the Rio Grande del Norte National Monument, and contains deposits that record volcanic, tectonic, and associated alluvial and colluvial processes over the past four million years. Sunshine Valley, named for the small locale of Sunshine, is incised by a series of northeast-trending dra
Geologic map of the Bailey 30' x 60' quadrangle, North-Central Colorado
The Bailey, Colo. 1:100,000-scale quadrangle lies within two physiographic and geologic provinces in central Colorado: 1) the Front Range and 2) South Park. Most of the Front Range is composed of Proterozoic rocks ranging in age from 1,790 Ma to 1,074 Ma. Along the eastern flanks and within the Denver Basin, sedimentary rocks ranging from Pennsylvanian to Cretaceous are deformed and steeply tilted
Geologic map of the Montoso Peak quadrangle, Santa Fe and Sandoval Counties, New Mexico
The Montoso Peak quadrangle is underlain by volcanic rocks and associated sediments of the Cerros del Rio volcanic field in the southern part of the Española Basin that record volcanic, faulting, alluvial, colluvial, and eolian processes over the past three million years. The geology was mapped from 1997 to 1999 and modified in 2004 to 2008. The geologic mapping was carried out in support of the U
Geologic map of the eastern half of the Vail 30' x 60' quadrangle, Eagle, Summit, and Grand Counties, Colorado
Recent mapping and geochronologic studies for the eastern half of the Vail 1:100,000-scale quadrangle have significantly improved our understanding of (1) Paleoproterozoic history of the basement rocks of the Gore Range and Williams Fork Mountains (western margin of the Front Range), (2) the Late Paleozoic history of the Gore fault system, (3) Laramide contractional tectonism, including deformatio
Geologic map of the Fraser 7.5-minute quadrangle, Grand County, Colorado
The geologic map of the Fraser quadrangle, Grand County, Colo., portrays the geology along the western boundary of the Front Range and the eastern part of the Fraser basin near the towns of Fraser and Winter Park. The oldest rocks in the quadrangle include gneiss, schist, and plutonic rocks of Paleoproterozoic age that are intruded by younger plutonic rocks of Mesoproterozoic age. These basement r
Filter Total Items: 14
Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado
Deposits of the North Park Formation of late Oligocene and Miocene age are locally exposed at small, widely spaced outcrops along the margins of the roughly northwest-trending North Park syncline in the southern part of North Park, a large intermontane topographic basin in Jackson County in north-central Colorado. These outcrops suggest that rocks and sediments of the North Park Formation consist
Authors
Ralph R. Shroba
Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains
This report describes, in a nontechnical style, the geologic history and mining activity in the Blue River region of Colorado, which includes all of Summit County. The geologic story begins with the formation of ancient basement rocks, as old as about 1700 million years, and continues with the deposition of sedimentary rocks on a vast erosional surface beginning in the Cambrian Period (about 530 m
Authors
Karl S. Kellogg, Bruce Bryant, Ralph R. Shroba
Pinedale glacial history of the upper Arkansas River valley: New moraine chronologies, modeling results, and geologic mapping
This field-trip guide outlines the glacial history of the upper Arkansas River valley, Colorado, and builds on a previous GSA field trip to the area in 2010. The following will be presented: (1) new cosmogenic 10Be exposure ages of moraine boulders from the Pinedale and Bull Lake glaciations (Marine Isotope Stages 2 and 6, respectively) located adjacent to the Twin Lakes Reservoir, (2) numerical m
Authors
Avriel D. Schweinsberg, Jason P. Briner, Ralph R. Shroba, Joseph M. Licciardi, Eric M. Leonard, Keith A. Brugger, Charles M. Russell
Preliminary geologic map of the Big Costilla Peak area, Taos County, New Mexico, and Costilla County, Colorado
This map covers the Big Costilla Peak, New Mex.‒Colo. quadrangle and adjacent parts of three other 7.5 minute quadrangles: Amalia, New Mex.‒Colo., Latir Peak, New Mex., and Comanche Point, New Mex. The study area is in the southwesternmost part of that segment of the Sangre de Cristo Mountains known as the Culebra Range; the Taos Range segment lies to the southwest of Costilla Creek and its tribut
Authors
Christopher J. Fridrich, Ralph R. Shroba, Adam M. Hudson
Beyond Colorado's Front Range - A new look at Laramide basin subsidence, sedimentation, and deformation in north-central Colorado
This field trip highlights recent research into the Laramide uplift, erosion, and sedimentation on the western side of the northern Colorado Front Range. The Laramide history of the North Park-Middle Park basin (designated the Colorado Headwaters Basin in this paper) is distinctly different from that of the Denver basin on the eastern flank of the range. The Denver basin stratigraphy records the t
Authors
James C. Cole, James H. Trexler, Patricia H. Cashman, Ian M. Miller, Ralph R. Shroba, Michael A. Cosca, Jeremiah B. Workman
Preliminary geologic map of the Vermejo Peak area, Colfax and Taos Counties, New Mexico and Las Animas and Costilla Counties, Colorado
This geologic map covers four 7.5-minute quadrangles-The Wall, NM-CO (New Mexico-Colorado), Vermejo Park, NM-CO, Ash Mountain, NM, and Van Bremmer Park, NM. The study area straddles the boundary between the eastern flank of the Sangre de Cristo Mountains and the western margin of the Raton Basin, with about two-thirds of the map area in the basin. The Raton Basin is a foreland basin that formed im
Authors
Christopher J. Fridrich, Ralph R. Shroba, Charles L. Pillmore, Adam M. Hudson
Ages of Quaternary Rio Grande terrace-fill deposits, Albuquerque area, New Mexico
Results from luminescence dating on 13 samples from the Albuquerque area show that major-drainage fluvial deposits represent significant periods of aggradation that formed paired, correlatable terraces on the east and west margins of the Rio Grande valley . The youngest terrace fills (Primero Alto) formed during late Pleistocene as a result of streamflow variations with climate cooling during Mari
Authors
Shannon Mahan, Byron D. Stone, Ralph R. Shroba
The Rocky Mountain glacial model; the Wind River Range, Wyoming
No abstract available.
Authors
D. E. Dahms, R. D. Hall, Ralph R. Shroba, C. J. Sorenson, E. A. Lynch, M. T. Applegarth
Quaternary stratigraphy, geomorphology, soils, and alpine archaeology in an alpine-to-plains transect, Colorado Front Range
No abstract available.
Authors
David P. Dethier, James B. Benedict, Peter W. Birkeland, Nel Caine, P. Thompson Davis, Richard F. Madole, Penny E. Patterson, Alan B. Price, Taylor F. Schildgen, Ralph R. Shroba
Eagle collapse center: Interpretation of evidence for late Cenozoic evaporite-related deformation in the Eagle River basin, Colorado
Evaporite tectonism resulted in deformation and collapse over an area of ~2500 km2 that is referred to as the Eagle collapse center. The collapse center includes much of the Eagle and Colorado River drainage basins between Vail, Dotsero, and McCoy, Colorado. The volume loss of evaporitic rocks by dissolution in the collapse center is estimated to be nearly 1700 km33 . Before ca. 10 Ma, Miocene bas
Authors
David J. Lidke, Mark R. Hudson, R. B. Scott, Ralph R. Shroba, Michael J. Kunk, W. J. Perry, R. M. Kirkham, James R. Budahn, R. K. Streufert, J.O. Stanley, B.L. Widmann
Soil relative dating of moraine and outwash-terrace sequences in the northern part of the upper Arkansas Valley, central Colorado, U.S.A.
Profile development indices for soils developed in moraines and outwash near Twin Lakes and in outwash near Leadville support the correlation of moraines with subdued morphology and two high outwash terraces with the Bull Lake glaciation (ca. 130-160 ka) and the correlation of hummocky moraines and two low outwash terraces with the Pinedale glaciation (ca. 14-47 ka). Elsewhere in the northern part
Authors
Alan R. Nelson, Ralph R. Shroba
Preliminary geologic map of the Rifle Quadrangle, Garfield County, Colorado
No abstract available.
Authors
Ralph R. Shroba, M. W. Green, G. M. Fairer