USGS scientist Ren Thompson (in yellow) explaining the geology of Wild and scenic Rivers to the astronauts and fellow instructors and NASA staff.
V. J. Grauch
V. J. S. ("Tien") Grauch has been employed by the U.S. Geological Survey in Denver, Colorado since 1977, where she is currently a senior research geophysicist with the Geology, Geophysics, and Geochemistry Science Center.
Her research interests include application of high-resolution aeromagnetic data to map intrasedimentary faults, integration of geologic and geophysical data to develop 3D geologic and hydrogeologic frameworks, the relation between magnetic sources and geology, interpretation of aeromagnetic data over rugged magnetic terrain, and development of new interpretation methods.
Education and Certifications
PhD (1986) in geophysics from Colorado School of Mines
BA (1975) in geology from Carleton College
Science and Products
Airborne Magnetic and Radiometric Survey, Colorado Mineral Belt, Southwest Block, 2023
This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the southwestern portion of the Colorado Mineral Belt, southwestern Colorado. The Colorado Mineral Belt is a broad, northeast-southwest trending alignment of historic mining districts that have produced multiple types of commodities, including critical minerals that a
Airborne magnetic and radiometric survey of the Wet Mountains and surrounding region, Custer and Fremont Counties, south-central Colorado, 2021
This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2
Airborne Geophysical Survey Inventory of the Conterminous United States, Alaska, Hawaii, and Puerto Rico (ver. 5.0, April 2024)
This data release is a compilation of the locations of airborne geophysical surveys in the United States. The inventory documents public airborne geophysical surveys primarily flown by or contracted by the USGS from 1943 to present. In addition, surveys from the State of Alaska, Department of Natural Resources, Division of Geological and Geophysical Surveys (DGGS): Airborne GeophysWeb, the Bureau
High Resolution Aeromagnetic Survey, Villa Grove, Colorado, USA, 2011
This data release includes data collected from the Villa Grove helicopter magnetic survey in northern San Luis Valley and Poncha Pass region in south-central Colorado, USA. The survey area extends over the northern part of Great Sand Dunes National Park, Poncha Pass and vicinity, and into the southern end of the Upper Arkansas Valley. It includes the communities of Crestone, Villa Grove, Saguache,
Data release for a paleomagnetic age estimate for the drainage of ancient Lake Alamosa, San Luis Valley, southwestern Colorado
Samples, sample depths, paleomagnetism, and magnetic susceptibility parameters are recorded for BP-3-USGS well, San Luis Valley, Southwestern Colorado
Updated aeromagnetic and gravity anomaly compilations and elevation-bathymetry models over Lake Superior
New gravity and magnetic compilations and elevation-bathymetry models have been compiled for the Lake Superior region. These data provide continuous sets of observations for geologic interpretations spanning political boundaries such as US States and the US-Canada border where bedrock geology is largely concealed beneath glacial deposits and surface water. These data are providing constraints for
Physical properties by geologic unit in the southern San Luis basin, New Mexico
Physical properties of geologic units are important for geophysical interpretation because they provide the tie between lithology and geophysical fields. For gravity data, the applicable physical property is bulk density, which is the overall mass per unit volume of rocks, sediments, and their pore spaces. Bulk dry density is the mass per unit volume measured when the sample is dry. Saturated den
Data for a Comprehensive Survey of Fault Zones, Breccias, and Fractures in and Flanking the Eastern Espanola Basin, Rio Grande Rift, New Mexico
This release provides the data for a comprehensive survey of geologic structures in the eastern Espaola Basin of the Rio Grande rift, New Mexico. The release includes data and analyses from 53 individual fault zones and 22 other brittle structures, such as breccia zones, joints, and veins, investigated at a total of just over 100 sites. Structures were examined and compared from poorly lithified T
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map boundaries were drawn to cover all of the “Poncha mountain
Geologic map of the Agua Fria quadrangle, Santa Fe County, New Mexico
No abstract available.
Aeromagnetic maps of the Uinta and Piceance Basins and vicinity, Utah and Colorado
In order to understand the evolution of sedimentary basins, it is important to understand their tectonic setting. In a U.S. Geological Survey (USGS) study of the Uinta and Piceance basins in Utah and Colorado, this understanding is approached through characterization of subsurface structure and lithology of a large region encompassing the basins. An important tool for interpreting these subsurface
Aeromagnetic maps of the Colorado River region including the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degrees quadrangles, California, Arizona, and Nevada
Aeromagnetic data for the Colorado river region have been compiled as part of the Pacific to Arizona Crustal Experiment (PACE) Project. The data are presented here in a series of six compilations for the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degree quadrangles, California, Arizona, and Nevada, at scales of 1:250,000 and 1:750,000. The scales and map areas are identical to those
By
Interpretive aeromagnetic map of the Eagle Mountains Wilderness Study Area, Riverside County, California
This report describes the interpretation of aeromagnetic surveys of the Eagle Mountains area, concentrating on the Eagle Mountains Wilderness Study Area (WSA). The interpretations are based on correlations with mapped surface geology by R. E. Powell, reproduced here from Powell and others (1984), as a base for the aeromagnetic data.
The Eagle Mountains Wilderness Study Area consists of about 49,72
USGS Training for NASA Astronauts
USGS scientist Ren Thompson (in yellow) explaining the geology of Wild and scenic Rivers to the astronauts and fellow instructors and NASA staff.
Filter Total Items: 97
Revisiting geophysical interpretations of the Midcontinent Rift below Lake Superior— Insights from GLIMPCE seismic-reflection line C
The 1.1 Ga Midcontinent Rift System (MRS) has been investigated in the Lake Superior region for more than a century. The most influential geophysical data for modern paradigms has come from seismic-reflection profiles collected by the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) in the late 1980s. We are revisiting seismic-reflection GLIMPCE line C by construc
Authors
V. J. S. Grauch, Samuel J. Heller, Laurel G. Woodruff, Esther K. Stewart
Compressional-wave seismic velocity, bulk density, and their empirical relations for geophysical modeling of the Midcontinent Rift System in the Lake Superior region
Compressional-wave seismic velocity (velocity) and bulk density (density) data were compiled from published sources for rock suites and earth materials that are significant for geophysical modeling of the Mesoproterozoic Midcontinent Rift System in the Lake Superior region. The data include laboratory measurements of outcrop and drill core samples, seismic refraction studies, and a sonic log from
Authors
V. J. S. Grauch
Exploring the geology of the Midcontinent Rift under western Lake Superior using a preliminary velocity model of seismic line GLIMPCE C
Seismic-reflection data were collected in the 1980s as part of the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) to investigate the 1.1 Ga Midcontinent Rift System (MRS). GLIMPCE Line C crosses western Lake Superior from north to south shores (Fig. 1 inset). Many previous workers have interpreted the MRS in Line C as an asymmetric central graben filled with 10–
Authors
V. J. S. Grauch, Samuel J. Heller, Esther K. Stewart, Laurel G. Woodruff
Integration of geophysical evidence suggests that anorthosite composes a significant portion of Grand Marais ridge, an inferred basement high in western Lake Superior
The Midcontinent Rift System (MRS) is expressed geophysically by a semi-linear, regional gravity high that trends across the Midcontinent and Great Lakes region of North America. The gravity high is interrupted by two prominent, semi-circular gravity lows, which have been interpreted from modeling and seismic-reflection sections as basement highs of Archean granite (Allen et al., 1997). One is cen
Authors
V. J. Grauch, Samuel J. Heller
Integrated geophysical analysis provides an alternate interpretation of the northern margin of the North American Midcontinent Rift System, Central Lake Superior
The Midcontinent Rift System (MRS) is a 1.1 Ga sequence of voluminous basaltic eruptions and multiple intrusions followed by widespread sedimentation that extends across the Midcontinent and northern Great Lakes region of North America. Previous workers have commonly used seismic-reflection data (Great Lakes International Multidisciplinary Program on Crustal Evolution [GLIMPCE] line A) to demonstr
Authors
V. J. Grauch, Eric D. Anderson, Samuel J. Heller, Esther K. Stewart, Laurel G. Woodruff
The US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI)—Providing framework geologic, geophysical, and elevation data to the nation’s critical mineral-bearing regions
New detailed mapping of the geologic resources of the Nation has the potential to significantly close the gap in the essential data needed to fuel a modern era of economic development and technological innovation, while at the same time dramatically enhancing our understanding of the fundamental way geology impacts everyday life, from the domestic critical mineral resources that are necessary for
Authors
Warren C. Day, Benjamin J. Drenth, Anne E. McCafferty, Anjana K. Shah, David A. Ponce, James V. Jones, V. J. Grauch
Finding the gaps in America’s magnetic maps
No abstract available.
Authors
Benjamin J. Drenth, V. J. Grauch
A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.
Interpretation of gravity, magnetotelluric, and aeromagnetic data in conjunction with geologic constraints reveals details of basin geometry, thickness, and spatiotemporal evolution of the southern San Luis Basin, one of the major basins of the northern Rio Grande rift. Spatial variations of low-density basin-fill thickness are estimated primarily using a 3D gravity inversion method that improves
Authors
Benjamin J. Drenth, V. J. Grauch, Kenzie J. Turner, Brian D. Rodriguez, Ren A. Thompson, Paul W. Bauer
A paleomagnetic age estimate for the draining of ancient Lake Alamosa, San Luis Valley, south-central Colorado, U.S.A.
In September 2009, a 99.4-m (326-ft) deep well was drilled proximal to Great Sand Dunes National Park and Preserve to explore the history and subsurface geology of the San Luis Valley, Colorado. Of particular interest was deciphering the evolution of ancient Lake Alamosa, which filled much of the San Luis Valley in the Pliocene and Pleistocene. Thick intervals of massive clay, recovered at the wel
Authors
Joshua K. Davis, Mark R. Hudson, V. J. S. Grauch
A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near Ta
Authors
V. J. S. Grauch, Paul W. Bauer, Benjamin J. Drenth, Keith I. Kelson
Geophysical expression of buried range-front embayment structure: Great Sand Dunes National Park, Rio Grande rift, Colorado
Great Sand Dunes National Park and Preserve (GRSA, Colorado) lies along the eastern margin of the San Luis Basin and the tectonically active Sangre de Cristo fault system that are part of the northern Rio Grande rift. GRSA lies within a prominent embayment in the range front where two separate sections of the Sangre de Cristo fault system intersect. Fault scarps are observed along both intersectin
Authors
Benjamin J. Drenth, V. J. Grauch, Chester A. Ruleman, Judith A Schenk
Geologic map and cross sections of the Embudo Fault Zone in the Southern Taos Valley, Taos County, New Mexico
The southern Taos Valley encompasses the physiographic and geologic transition zone between the Picuris Mountains and the San Luis Basin of the Rio Grande rift. The Embudo fault zone is the rift transfer structure that has accommodated the kinematic disparities between the San Luis Basin and the Española Basin during Neogene rift extension. The eastern terminus of the transfer zone coincides with
Authors
Paul W. Bauer, Keith I. Kelson, V. J. S. Grauch, Benjamin J. Drenth, Peggy S. Johnson, Scott B. Aby, Brigitte Felix
Science and Products
Airborne Magnetic and Radiometric Survey, Colorado Mineral Belt, Southwest Block, 2023
This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the southwestern portion of the Colorado Mineral Belt, southwestern Colorado. The Colorado Mineral Belt is a broad, northeast-southwest trending alignment of historic mining districts that have produced multiple types of commodities, including critical minerals that a
Airborne magnetic and radiometric survey of the Wet Mountains and surrounding region, Custer and Fremont Counties, south-central Colorado, 2021
This data release provides digital flight-line and gridded data for a high-resolution airborne magnetic and radiometric survey over the region surrounding the Wet Mountains of southern Colorado, including parts of Custer and Fremont Counties. Data for this survey were collected by Sander Geophysics Limited International (SGL) under contract with the USGS. The survey was flown in June and July of 2
Airborne Geophysical Survey Inventory of the Conterminous United States, Alaska, Hawaii, and Puerto Rico (ver. 5.0, April 2024)
This data release is a compilation of the locations of airborne geophysical surveys in the United States. The inventory documents public airborne geophysical surveys primarily flown by or contracted by the USGS from 1943 to present. In addition, surveys from the State of Alaska, Department of Natural Resources, Division of Geological and Geophysical Surveys (DGGS): Airborne GeophysWeb, the Bureau
High Resolution Aeromagnetic Survey, Villa Grove, Colorado, USA, 2011
This data release includes data collected from the Villa Grove helicopter magnetic survey in northern San Luis Valley and Poncha Pass region in south-central Colorado, USA. The survey area extends over the northern part of Great Sand Dunes National Park, Poncha Pass and vicinity, and into the southern end of the Upper Arkansas Valley. It includes the communities of Crestone, Villa Grove, Saguache,
Data release for a paleomagnetic age estimate for the drainage of ancient Lake Alamosa, San Luis Valley, southwestern Colorado
Samples, sample depths, paleomagnetism, and magnetic susceptibility parameters are recorded for BP-3-USGS well, San Luis Valley, Southwestern Colorado
Updated aeromagnetic and gravity anomaly compilations and elevation-bathymetry models over Lake Superior
New gravity and magnetic compilations and elevation-bathymetry models have been compiled for the Lake Superior region. These data provide continuous sets of observations for geologic interpretations spanning political boundaries such as US States and the US-Canada border where bedrock geology is largely concealed beneath glacial deposits and surface water. These data are providing constraints for
Physical properties by geologic unit in the southern San Luis basin, New Mexico
Physical properties of geologic units are important for geophysical interpretation because they provide the tie between lithology and geophysical fields. For gravity data, the applicable physical property is bulk density, which is the overall mass per unit volume of rocks, sediments, and their pore spaces. Bulk dry density is the mass per unit volume measured when the sample is dry. Saturated den
Data for a Comprehensive Survey of Fault Zones, Breccias, and Fractures in and Flanking the Eastern Espanola Basin, Rio Grande Rift, New Mexico
This release provides the data for a comprehensive survey of geologic structures in the eastern Espaola Basin of the Rio Grande rift, New Mexico. The release includes data and analyses from 53 individual fault zones and 22 other brittle structures, such as breccia zones, joints, and veins, investigated at a total of just over 100 sites. Structures were examined and compared from poorly lithified T
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map boundaries were drawn to cover all of the “Poncha mountain
Geologic map of the Agua Fria quadrangle, Santa Fe County, New Mexico
No abstract available.
Aeromagnetic maps of the Uinta and Piceance Basins and vicinity, Utah and Colorado
In order to understand the evolution of sedimentary basins, it is important to understand their tectonic setting. In a U.S. Geological Survey (USGS) study of the Uinta and Piceance basins in Utah and Colorado, this understanding is approached through characterization of subsurface structure and lithology of a large region encompassing the basins. An important tool for interpreting these subsurface
Aeromagnetic maps of the Colorado River region including the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degrees quadrangles, California, Arizona, and Nevada
Aeromagnetic data for the Colorado river region have been compiled as part of the Pacific to Arizona Crustal Experiment (PACE) Project. The data are presented here in a series of six compilations for the Kingman, Needles, Salton Sea, and El Centro 1 degree by 2 degree quadrangles, California, Arizona, and Nevada, at scales of 1:250,000 and 1:750,000. The scales and map areas are identical to those
By
Interpretive aeromagnetic map of the Eagle Mountains Wilderness Study Area, Riverside County, California
This report describes the interpretation of aeromagnetic surveys of the Eagle Mountains area, concentrating on the Eagle Mountains Wilderness Study Area (WSA). The interpretations are based on correlations with mapped surface geology by R. E. Powell, reproduced here from Powell and others (1984), as a base for the aeromagnetic data.
The Eagle Mountains Wilderness Study Area consists of about 49,72
USGS Training for NASA Astronauts
USGS scientist Ren Thompson (in yellow) explaining the geology of Wild and scenic Rivers to the astronauts and fellow instructors and NASA staff.
USGS scientist Ren Thompson (in yellow) explaining the geology of Wild and scenic Rivers to the astronauts and fellow instructors and NASA staff.
Filter Total Items: 97
Revisiting geophysical interpretations of the Midcontinent Rift below Lake Superior— Insights from GLIMPCE seismic-reflection line C
The 1.1 Ga Midcontinent Rift System (MRS) has been investigated in the Lake Superior region for more than a century. The most influential geophysical data for modern paradigms has come from seismic-reflection profiles collected by the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) in the late 1980s. We are revisiting seismic-reflection GLIMPCE line C by construc
Authors
V. J. S. Grauch, Samuel J. Heller, Laurel G. Woodruff, Esther K. Stewart
Compressional-wave seismic velocity, bulk density, and their empirical relations for geophysical modeling of the Midcontinent Rift System in the Lake Superior region
Compressional-wave seismic velocity (velocity) and bulk density (density) data were compiled from published sources for rock suites and earth materials that are significant for geophysical modeling of the Mesoproterozoic Midcontinent Rift System in the Lake Superior region. The data include laboratory measurements of outcrop and drill core samples, seismic refraction studies, and a sonic log from
Authors
V. J. S. Grauch
Exploring the geology of the Midcontinent Rift under western Lake Superior using a preliminary velocity model of seismic line GLIMPCE C
Seismic-reflection data were collected in the 1980s as part of the Great Lakes International Multidisciplinary Program on Crustal Evolution (GLIMPCE) to investigate the 1.1 Ga Midcontinent Rift System (MRS). GLIMPCE Line C crosses western Lake Superior from north to south shores (Fig. 1 inset). Many previous workers have interpreted the MRS in Line C as an asymmetric central graben filled with 10–
Authors
V. J. S. Grauch, Samuel J. Heller, Esther K. Stewart, Laurel G. Woodruff
Integration of geophysical evidence suggests that anorthosite composes a significant portion of Grand Marais ridge, an inferred basement high in western Lake Superior
The Midcontinent Rift System (MRS) is expressed geophysically by a semi-linear, regional gravity high that trends across the Midcontinent and Great Lakes region of North America. The gravity high is interrupted by two prominent, semi-circular gravity lows, which have been interpreted from modeling and seismic-reflection sections as basement highs of Archean granite (Allen et al., 1997). One is cen
Authors
V. J. Grauch, Samuel J. Heller
Integrated geophysical analysis provides an alternate interpretation of the northern margin of the North American Midcontinent Rift System, Central Lake Superior
The Midcontinent Rift System (MRS) is a 1.1 Ga sequence of voluminous basaltic eruptions and multiple intrusions followed by widespread sedimentation that extends across the Midcontinent and northern Great Lakes region of North America. Previous workers have commonly used seismic-reflection data (Great Lakes International Multidisciplinary Program on Crustal Evolution [GLIMPCE] line A) to demonstr
Authors
V. J. Grauch, Eric D. Anderson, Samuel J. Heller, Esther K. Stewart, Laurel G. Woodruff
The US Geological Survey’s Earth Mapping Resources Initiative (Earth MRI)—Providing framework geologic, geophysical, and elevation data to the nation’s critical mineral-bearing regions
New detailed mapping of the geologic resources of the Nation has the potential to significantly close the gap in the essential data needed to fuel a modern era of economic development and technological innovation, while at the same time dramatically enhancing our understanding of the fundamental way geology impacts everyday life, from the domestic critical mineral resources that are necessary for
Authors
Warren C. Day, Benjamin J. Drenth, Anne E. McCafferty, Anjana K. Shah, David A. Ponce, James V. Jones, V. J. Grauch
Finding the gaps in America’s magnetic maps
No abstract available.
Authors
Benjamin J. Drenth, V. J. Grauch
A shallow rift basin segmented in space and time: The southern San Luis Basin, Rio Grande rift, northern New Mexico, U.S.A.
Interpretation of gravity, magnetotelluric, and aeromagnetic data in conjunction with geologic constraints reveals details of basin geometry, thickness, and spatiotemporal evolution of the southern San Luis Basin, one of the major basins of the northern Rio Grande rift. Spatial variations of low-density basin-fill thickness are estimated primarily using a 3D gravity inversion method that improves
Authors
Benjamin J. Drenth, V. J. Grauch, Kenzie J. Turner, Brian D. Rodriguez, Ren A. Thompson, Paul W. Bauer
A paleomagnetic age estimate for the draining of ancient Lake Alamosa, San Luis Valley, south-central Colorado, U.S.A.
In September 2009, a 99.4-m (326-ft) deep well was drilled proximal to Great Sand Dunes National Park and Preserve to explore the history and subsurface geology of the San Luis Valley, Colorado. Of particular interest was deciphering the evolution of ancient Lake Alamosa, which filled much of the San Luis Valley in the Pliocene and Pleistocene. Thick intervals of massive clay, recovered at the wel
Authors
Joshua K. Davis, Mark R. Hudson, V. J. S. Grauch
A shifting rift—Geophysical insights into the evolution of Rio Grande rift margins and the Embudo transfer zone near Taos, New Mexico
We present a detailed example of how a subbasin develops adjacent to a transfer zone in the Rio Grande rift. The Embudo transfer zone in the Rio Grande rift is considered one of the classic examples and has been used as the inspiration for several theoretical models. Despite this attention, the history of its development into a major rift structure is poorly known along its northern extent near Ta
Authors
V. J. S. Grauch, Paul W. Bauer, Benjamin J. Drenth, Keith I. Kelson
Geophysical expression of buried range-front embayment structure: Great Sand Dunes National Park, Rio Grande rift, Colorado
Great Sand Dunes National Park and Preserve (GRSA, Colorado) lies along the eastern margin of the San Luis Basin and the tectonically active Sangre de Cristo fault system that are part of the northern Rio Grande rift. GRSA lies within a prominent embayment in the range front where two separate sections of the Sangre de Cristo fault system intersect. Fault scarps are observed along both intersectin
Authors
Benjamin J. Drenth, V. J. Grauch, Chester A. Ruleman, Judith A Schenk
Geologic map and cross sections of the Embudo Fault Zone in the Southern Taos Valley, Taos County, New Mexico
The southern Taos Valley encompasses the physiographic and geologic transition zone between the Picuris Mountains and the San Luis Basin of the Rio Grande rift. The Embudo fault zone is the rift transfer structure that has accommodated the kinematic disparities between the San Luis Basin and the Española Basin during Neogene rift extension. The eastern terminus of the transfer zone coincides with
Authors
Paul W. Bauer, Keith I. Kelson, V. J. S. Grauch, Benjamin J. Drenth, Peggy S. Johnson, Scott B. Aby, Brigitte Felix