Ralph Shroba
Ralph Shroba is a Scientist Emeritus with the Geosciences and Environmental Change Science Center
Science and Products
Filter Total Items: 42
Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado 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...
Authors
Ralph R. Shroba
Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains 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...
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 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)...
Authors
Avriel D. Schweinsberg, Jason P. Briner, Ralph R. Shroba, Joseph M. Licciardi, Eric M. Leonard, Keith A. Brugger, Charles M. Russell
Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado
The Sunshine Valley-Costilla Plain, a structural subbasin of the greater San Luis Basin of the northern Rio Grande rift, is bounded to the north and south by the San Luis Hills and the Red River fault zone, respectively. Surficial mapping, neotectonic investigations, geochronology, and geophysics demonstrate that the structural, volcanic, and geomorphic evolution of the basin involves...
Authors
C.A. Ruleman, R. A. Thompson, R. R. Shroba, M. Anderson, B. J. Drenth, J. Rotzien, J. Lyon
Preliminary geologic map of the Big Costilla Peak area, Taos County, New Mexico, and Costilla County, Colorado 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...
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 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...
Authors
James C. Cole, James H. Trexler, Patricia H. Cashman, Ian M. Miller, Ralph R. Shroba, Michael A. Cosca, Jeremiah B. Workman
Data Release for Geologic Map of Petroglyph National Monument and Vicinity, Bernalillo County, New Mexico 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...
Data Release for Geologic Map of the Fort Collins 30' x 60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming 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 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...
Data release of Geologic Map of the Upper Arkansas River Valley Region, North-Central, Colorado 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...
Filter Total Items: 26
Geologic map of Petroglyph National Monument and vicinity, Bernalillo County, New Mexico 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...
Geologic map of the Fort Collins 30'×60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming 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...
Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado 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...
Geologic map of the upper Arkansas River valley region, north-central Colorado 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...
Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado 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...
Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado 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...
Science and Products
Filter Total Items: 42
Geologic framework, age, and lithologic characteristics of the North Park Formation in North Park, north-central Colorado 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...
Authors
Ralph R. Shroba
Mountains, glaciers, and mines—The geological story of the Blue River valley, Colorado, and its surrounding mountains 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...
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 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)...
Authors
Avriel D. Schweinsberg, Jason P. Briner, Ralph R. Shroba, Joseph M. Licciardi, Eric M. Leonard, Keith A. Brugger, Charles M. Russell
Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado
The Sunshine Valley-Costilla Plain, a structural subbasin of the greater San Luis Basin of the northern Rio Grande rift, is bounded to the north and south by the San Luis Hills and the Red River fault zone, respectively. Surficial mapping, neotectonic investigations, geochronology, and geophysics demonstrate that the structural, volcanic, and geomorphic evolution of the basin involves...
Authors
C.A. Ruleman, R. A. Thompson, R. R. Shroba, M. Anderson, B. J. Drenth, J. Rotzien, J. Lyon
Preliminary geologic map of the Big Costilla Peak area, Taos County, New Mexico, and Costilla County, Colorado 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...
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 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...
Authors
James C. Cole, James H. Trexler, Patricia H. Cashman, Ian M. Miller, Ralph R. Shroba, Michael A. Cosca, Jeremiah B. Workman
Data Release for Geologic Map of Petroglyph National Monument and Vicinity, Bernalillo County, New Mexico 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...
Data Release for Geologic Map of the Fort Collins 30' x 60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming 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 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...
Data release of Geologic Map of the Upper Arkansas River Valley Region, North-Central, Colorado 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...
Filter Total Items: 26
Geologic map of Petroglyph National Monument and vicinity, Bernalillo County, New Mexico 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...
Geologic map of the Fort Collins 30'×60' quadrangle, Larimer and Jackson Counties, Colorado, and Albany and Laramie Counties, Wyoming 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...
Geologic map of the San Antonio Mountain area, northern New Mexico and southern Colorado 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...
Geologic map of the upper Arkansas River valley region, north-central Colorado 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...
Geologic map of the Alamosa 30’ × 60’ quadrangle, south-central Colorado 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...
Geologic map of the Granite 7.5' quadrangle, Lake and Chaffee Counties, Colorado 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...