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Jeremiah Workman

Jeremy Workman is a Geologist with the Geosciences and Environmental Change Science Center

Science and Products

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Rippling marine deposits with hammer shown for scale

Sedimentology and Structure Working Group

The Sedimentology and Structure Working Group supports the Geologic Framework of the Intermountain West Project by conducting research on sedimentary rocks and structural deformation to determine the processes controlling tectonic uplift, accommodation, and sedimentation, ultimately to develop stratigraphic and structural frameworks that expand the utility of geologic map relationships for process...
By
Geosciences and Environmental Change Science Center
link

Sedimentology and Structure Working Group

The Sedimentology and Structure Working Group supports the Geologic Framework of the Intermountain West Project by conducting research on sedimentary rocks and structural deformation to determine the processes controlling tectonic uplift, accommodation, and sedimentation, ultimately to develop stratigraphic and structural frameworks that expand the utility of geologic map relationships for process...
Learn More
link
Close up view of metagreywacke

Igneous and Metamorphic Working Group

The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West Project by conducting research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West and their implications for mineral resource exploration and tectonic history.
By
Geosciences and Environmental Change Science Center
link

Igneous and Metamorphic Working Group

The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West Project by conducting research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West and their implications for mineral resource exploration and tectonic history.
Learn More
link
Mt. Ouray, Colorado with aspen colors

Geologic Framework of the Intermountain West

The Geologic Framework of the Intermountain West (IMW) Project is creating a seamless, integrated, geologic map database that spans the Intermountain West region. The database will serve enhanced geologic map data to support geoscience research, environmental and resource assessments, and the communication of geologic information for all U.S. Geological Survey stakeholders. This innovative...
By
Geosciences and Environmental Change Science Center
link

Geologic Framework of the Intermountain West

The Geologic Framework of the Intermountain West (IMW) Project is creating a seamless, integrated, geologic map database that spans the Intermountain West region. The database will serve enhanced geologic map data to support geoscience research, environmental and resource assessments, and the communication of geologic information for all U.S. Geological Survey stakeholders. This innovative...
Learn More

Bedrock geologic map database for the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado

This data release presents geologic map data for the bedrock geology of the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted b
By
Geosciences and Environmental Change Science Center

Bedrock geologic map database for the Durango 1-degree x 2-degree quadrangle, southern Colorado: Contributions to the National Geologic Map (ver. 2.0, June 2024)

This data release presents geologic map data for the bedrock geology of the Durango 1-degree by 2-degree quadrangle. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted based on digital elevation model and nat
By
Geosciences and Environmental Change Science Center

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.
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

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
By
Energy Resources Program, Mineral Resources Program, National Cooperative Geologic Mapping Program, National Laboratories Program, Science and Decisions Center, Geosciences and Environmental Change Science Center

Geologic map of the Sand Creek Pass quadrangle, Larimer County, Colorado, and Albany County, Wyoming

New geologic mapping within the Sand Creek Pass 7.5 minute quadrangle defines geologic relationships within the northern Front Range of Colorado along the Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping; Eaton Reservoir 7.5 minute quadrangle to the east (2008), granite of the Rawah batholith to the sout
By
Ecosystems Mission Area, Geosciences and Environmental Change Science Center

Geologic map of the Hidden Hills Ranch Quadrangle, Clark County, Nevada

The prominent structural feature in the Pahrump Valley is the right-lateral Pahrump-Stewart Valley fault system (PSV) (Anderson and others, 1995b), which is the central segment of the State Line fault system as defined by Blakely and others (1998). The main trace of this fault system, as shown in figure 1A, strikes northwest along the California-Nevada state line through Pahrump and Stewart Valley
By
Geosciences and Environmental Change Science Center

Geologic Map of the Eaton Reservoir Quadrangle, Larimer County, Colorado and Albany County, Wyoming

New geologic mapping of the Eaton Reservoir 7.5' quadrangle defines geologic relationships in the northern Front Range along the Colorado/Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping (Tweto, 1979; Camp, 1979; Burch, 1983) and some minor site-specific studies (Carlson and Marsh, 1986; W. Braddock, unp
By
Geosciences and Environmental Change Science Center

Geologic and geophysical maps of the Las Vegas 30' x 60' quadrangle, Clark and Nye counties, Nevada, and Inyo County, California

Las Vegas and Pahrump are two of the fastest growing cities in the US, and the shortage of water looms as among the greatest future problems for these cities. These new maps of the Las Vegas 30 x 60-minute quadrangle provide a geologic and geophysical framework and fundamental earth science database needed to address societal issues such as ground water supply and contamination, surface flood, la
By
Geosciences and Environmental Change Science Center

Geologic map of the Mound Spring quadrangle, Nye and Clark Counties, Nevada, and Inyo County, California

The Mound Spring quadrangle, the southwestern-most 7.5' quadrangle of the area of the Las Vegas 1:100,000-scale quadrangle, is entirely within the Pahrump Valley, spanning the Nevada/California State line. New geologic mapping of the predominantly Quaternary materials is combined with new studies of gravity and geochronology in this quadrangle. Eleven predominantly fine-grained units are delinea

Geologic Map of the Central Marysvale Volcanic Field, Southwestern Utah

The geologic map of the central Marysvale volcanic field, southwestern Utah, shows the geology at 1:100,000 scale of the heart of one of the largest Cenozoic volcanic fields in the Western United States. The map shows the area of 38 degrees 15' to 38 degrees 42'30' N., and 112 degrees to 112 degrees 37'30' W. The Marysvale field occurs mostly in the High Plateaus, a subprovince of the Colorado

Geologic map of the Death Valley ground-water model area, Nevada and California

No abstract available.

Geologic map of the Littlefield 30' x 60' quadrangle, Mohave County, northwestern Arizona

This map is one result of the U.S. Geological Survey's intent to provide geologic map coverage and a better understanding of the transition in regional geology between the Basin and Range and Colorado Plateaus in southeastern Nevada, southwestern Utah, and northwestern Arizona. Information gained from this regional study provides a better understanding of the tectonic and magmatic evolution of an

Paleogene sedimentary basin development in southern Nevada, USA

The cause of the transition from Mesozoic and early Cenozoic crustal shortening to later extension in the western United States is debated. In many parts of the extant Sevier hinterland, now the Basin and Range Province, the sedimentary sections that provide the most direct record of that transition remain poorly studied and lack meaningful age control. In this paper, we present field characteriza
Authors
Jens-Erik Lundstern, Theresa Maude Schwartz, Cameron Mark Mercer, Joseph P. Colgan, Jeremiah B. Workman, Leah E. Morgan
By
Geosciences and Environmental Change Science Center, Geology, Geophysics, and Geochemistry Science Center

The Seamless Integrated Geologic Mapping (SIGMa) extension to the Geologic Map Schema (GeMS)

Geologic maps are the fundamental building blocks of surface and subsurface three-dimensional geologic framework models of the Earth’s crust. However, as the production and availability of geologic map databases continues to increase, inconsistent data models and the lack of synthesized, national geologic map data at scales appropriate for informed decision making negatively affect the functional
Authors
Kenzie J. Turner, Jeremiah B. Workman, Joseph P. Colgan, Amy K. Gilmer, Margaret E. Berry, Samuel Johnstone, Kathleen F. Warrell, Marieke Dechesne, D. Paco VanSistine, Ren A. Thompson, Adam M. Hudson, Kristine L. Zellman, Donald S. Sweetkind, Chester A. Ruleman
By
Geosciences and Environmental Change Science Center

A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link

Owing to the lack of temporally well-constrained Ediacaran fossil localities containing overlapping biotic assemblages, it has remained uncertain if the latest Ediacaran (ca 550–541 Ma) assemblages reflect systematic biological turnover or environmental, taphonomic or biogeographic biases. Here, we report new latest Ediacaran fossil discoveries from the lower member of the Wood Canyon Formation in
Authors
E. F. Smith, L. L. Nelson, S. M. Tweedt, H. Zeng, Jeremiah B. Workman
By
Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Integration of tectonic, sedimentary, and geohydrologic processes leading to a small-scale extension model for the Mormon Mountains area north of Lake Mead, Lincoln County, Nevada

Scattered remnants of highly diverse stratigraphic sections of Tertiary lacustrine limestone, andesite flows, and 23.8–18.2 Ma regional ash-flow tuffs on the north flank of the Mormon Mountains record previously unrecognized deformation, which we interpret as pre–17 Ma uplift and possibly weak extension on the north flank of a growing dome. Directly to the north of the Mormon dome, 17–14 Ma ash-fl
Authors
R. Ernest Anderson, Tracey J. Felger, Sharon F. Diehl, William R. Page, Jeremiah B. Workman
By
Geology, Minerals, Energy, and Geophysics Science Center

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
By
Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center

Digital Geologic Map of the Nevada Test Site and Vicinity, Nye, Lincoln, and Clark Counties, Nevada, and Inyo County, California

This digital geologic map of the Nevada Test Site (NTS) and vicinity, as well as its accompanying digital geophysical maps, are compiled at 1:100,000 scale. The map compilation presents new polygon (geologic map unit contacts), line (fault, fold axis, metamorphic isograd, dike, and caldera wall) and point (structural attitude) vector data for the NTS and vicinity, Nye, Lincoln, and Clark Counties,
Authors
Janet L. Slate, Margaret E. Berry, Peter D. Rowley, Christopher J. Fridrich, Karen S. Morgan, Jeremiah B. Workman, Owen D. Young, Gary L. Dixon, Van S. Williams, Edwin H. McKee, David A. Ponce, Thomas G. Hildenbrand, W. C. Swadley, Scott C. Lundstrom, E. Bartlett Ekren, Richard G. Warren, J. C. Cole, Robert J. Fleck, Marvin A. Lanphere, David A. Sawyer, Scott A. Minor, Daniel J. Grunwald, Randell J. Laczniak, Christopher M. Menges, James C. Yount, Angela S. Jayko

Preliminary geologic map of the Moapa West Quadrangle, Clark County, Nevada

No abstract available.
Authors
Dwight L. Schmidt, William R. Page, Jeremiah B. Workman

Evaluation of shorelines along Lake Mohave, Lake Mead National Recreation Area, Nevada and Arizona

The hdpw (head-in-a-pumping-well) program described in this report is a post-processor that calculates the head in a pumping well based on thesimulated head at a finite-difference model cell that contains the well. The calculations are based on the Thiem equation. The hdpw code works with the U.S. Geological Survey modular finite-difference ground-water flow model, which is commonly called MOD
Authors
Jeremiah B. Workman

Science and Products

link
Rippling marine deposits with hammer shown for scale

Sedimentology and Structure Working Group

The Sedimentology and Structure Working Group supports the Geologic Framework of the Intermountain West Project by conducting research on sedimentary rocks and structural deformation to determine the processes controlling tectonic uplift, accommodation, and sedimentation, ultimately to develop stratigraphic and structural frameworks that expand the utility of geologic map relationships for process...
By
Geosciences and Environmental Change Science Center
link

Sedimentology and Structure Working Group

The Sedimentology and Structure Working Group supports the Geologic Framework of the Intermountain West Project by conducting research on sedimentary rocks and structural deformation to determine the processes controlling tectonic uplift, accommodation, and sedimentation, ultimately to develop stratigraphic and structural frameworks that expand the utility of geologic map relationships for process...
Learn More
link
Close up view of metagreywacke

Igneous and Metamorphic Working Group

The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West Project by conducting research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West and their implications for mineral resource exploration and tectonic history.
By
Geosciences and Environmental Change Science Center
link

Igneous and Metamorphic Working Group

The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West Project by conducting research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West and their implications for mineral resource exploration and tectonic history.
Learn More
link
Mt. Ouray, Colorado with aspen colors

Geologic Framework of the Intermountain West

The Geologic Framework of the Intermountain West (IMW) Project is creating a seamless, integrated, geologic map database that spans the Intermountain West region. The database will serve enhanced geologic map data to support geoscience research, environmental and resource assessments, and the communication of geologic information for all U.S. Geological Survey stakeholders. This innovative...
By
Geosciences and Environmental Change Science Center
link

Geologic Framework of the Intermountain West

The Geologic Framework of the Intermountain West (IMW) Project is creating a seamless, integrated, geologic map database that spans the Intermountain West region. The database will serve enhanced geologic map data to support geoscience research, environmental and resource assessments, and the communication of geologic information for all U.S. Geological Survey stakeholders. This innovative...
Learn More

Bedrock geologic map database for the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado

This data release presents geologic map data for the bedrock geology of the Blanca Peak, Walsenburg, Trinidad, and Alamosa 30' x 60' quadrangles, Colorado. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted b
By
Geosciences and Environmental Change Science Center

Bedrock geologic map database for the Durango 1-degree x 2-degree quadrangle, southern Colorado: Contributions to the National Geologic Map (ver. 2.0, June 2024)

This data release presents geologic map data for the bedrock geology of the Durango 1-degree by 2-degree quadrangle. Geologic mapping incorporates new interpretive contributions and compilation from published geologic map data sources primarily ranging from 1:24,000 to 1:50,000 scale. Much of the geology incorporated from published geologic maps is adjusted based on digital elevation model and nat
By
Geosciences and Environmental Change Science Center

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.
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

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
By
Energy Resources Program, Mineral Resources Program, National Cooperative Geologic Mapping Program, National Laboratories Program, Science and Decisions Center, Geosciences and Environmental Change Science Center

Geologic map of the Sand Creek Pass quadrangle, Larimer County, Colorado, and Albany County, Wyoming

New geologic mapping within the Sand Creek Pass 7.5 minute quadrangle defines geologic relationships within the northern Front Range of Colorado along the Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping; Eaton Reservoir 7.5 minute quadrangle to the east (2008), granite of the Rawah batholith to the sout
By
Ecosystems Mission Area, Geosciences and Environmental Change Science Center

Geologic map of the Hidden Hills Ranch Quadrangle, Clark County, Nevada

The prominent structural feature in the Pahrump Valley is the right-lateral Pahrump-Stewart Valley fault system (PSV) (Anderson and others, 1995b), which is the central segment of the State Line fault system as defined by Blakely and others (1998). The main trace of this fault system, as shown in figure 1A, strikes northwest along the California-Nevada state line through Pahrump and Stewart Valley
By
Geosciences and Environmental Change Science Center

Geologic Map of the Eaton Reservoir Quadrangle, Larimer County, Colorado and Albany County, Wyoming

New geologic mapping of the Eaton Reservoir 7.5' quadrangle defines geologic relationships in the northern Front Range along the Colorado/Wyoming border approximately 35 km south of Laramie, Wyo. Previous mapping within the quadrangle was limited to regional reconnaissance mapping (Tweto, 1979; Camp, 1979; Burch, 1983) and some minor site-specific studies (Carlson and Marsh, 1986; W. Braddock, unp
By
Geosciences and Environmental Change Science Center

Geologic and geophysical maps of the Las Vegas 30' x 60' quadrangle, Clark and Nye counties, Nevada, and Inyo County, California

Las Vegas and Pahrump are two of the fastest growing cities in the US, and the shortage of water looms as among the greatest future problems for these cities. These new maps of the Las Vegas 30 x 60-minute quadrangle provide a geologic and geophysical framework and fundamental earth science database needed to address societal issues such as ground water supply and contamination, surface flood, la
By
Geosciences and Environmental Change Science Center

Geologic map of the Mound Spring quadrangle, Nye and Clark Counties, Nevada, and Inyo County, California

The Mound Spring quadrangle, the southwestern-most 7.5' quadrangle of the area of the Las Vegas 1:100,000-scale quadrangle, is entirely within the Pahrump Valley, spanning the Nevada/California State line. New geologic mapping of the predominantly Quaternary materials is combined with new studies of gravity and geochronology in this quadrangle. Eleven predominantly fine-grained units are delinea

Geologic Map of the Central Marysvale Volcanic Field, Southwestern Utah

The geologic map of the central Marysvale volcanic field, southwestern Utah, shows the geology at 1:100,000 scale of the heart of one of the largest Cenozoic volcanic fields in the Western United States. The map shows the area of 38 degrees 15' to 38 degrees 42'30' N., and 112 degrees to 112 degrees 37'30' W. The Marysvale field occurs mostly in the High Plateaus, a subprovince of the Colorado

Geologic map of the Death Valley ground-water model area, Nevada and California

No abstract available.

Geologic map of the Littlefield 30' x 60' quadrangle, Mohave County, northwestern Arizona

This map is one result of the U.S. Geological Survey's intent to provide geologic map coverage and a better understanding of the transition in regional geology between the Basin and Range and Colorado Plateaus in southeastern Nevada, southwestern Utah, and northwestern Arizona. Information gained from this regional study provides a better understanding of the tectonic and magmatic evolution of an

Paleogene sedimentary basin development in southern Nevada, USA

The cause of the transition from Mesozoic and early Cenozoic crustal shortening to later extension in the western United States is debated. In many parts of the extant Sevier hinterland, now the Basin and Range Province, the sedimentary sections that provide the most direct record of that transition remain poorly studied and lack meaningful age control. In this paper, we present field characteriza
Authors
Jens-Erik Lundstern, Theresa Maude Schwartz, Cameron Mark Mercer, Joseph P. Colgan, Jeremiah B. Workman, Leah E. Morgan
By
Geosciences and Environmental Change Science Center, Geology, Geophysics, and Geochemistry Science Center

The Seamless Integrated Geologic Mapping (SIGMa) extension to the Geologic Map Schema (GeMS)

Geologic maps are the fundamental building blocks of surface and subsurface three-dimensional geologic framework models of the Earth’s crust. However, as the production and availability of geologic map databases continues to increase, inconsistent data models and the lack of synthesized, national geologic map data at scales appropriate for informed decision making negatively affect the functional
Authors
Kenzie J. Turner, Jeremiah B. Workman, Joseph P. Colgan, Amy K. Gilmer, Margaret E. Berry, Samuel Johnstone, Kathleen F. Warrell, Marieke Dechesne, D. Paco VanSistine, Ren A. Thompson, Adam M. Hudson, Kristine L. Zellman, Donald S. Sweetkind, Chester A. Ruleman
By
Geosciences and Environmental Change Science Center

A cosmopolitan late Ediacaran biotic assemblage: new fossils from Nevada and Namibia support a global biostratigraphic link

Owing to the lack of temporally well-constrained Ediacaran fossil localities containing overlapping biotic assemblages, it has remained uncertain if the latest Ediacaran (ca 550–541 Ma) assemblages reflect systematic biological turnover or environmental, taphonomic or biogeographic biases. Here, we report new latest Ediacaran fossil discoveries from the lower member of the Wood Canyon Formation in
Authors
E. F. Smith, L. L. Nelson, S. M. Tweedt, H. Zeng, Jeremiah B. Workman
By
Groundwater and Streamflow Information Program, Geosciences and Environmental Change Science Center

Integration of tectonic, sedimentary, and geohydrologic processes leading to a small-scale extension model for the Mormon Mountains area north of Lake Mead, Lincoln County, Nevada

Scattered remnants of highly diverse stratigraphic sections of Tertiary lacustrine limestone, andesite flows, and 23.8–18.2 Ma regional ash-flow tuffs on the north flank of the Mormon Mountains record previously unrecognized deformation, which we interpret as pre–17 Ma uplift and possibly weak extension on the north flank of a growing dome. Directly to the north of the Mormon dome, 17–14 Ma ash-fl
Authors
R. Ernest Anderson, Tracey J. Felger, Sharon F. Diehl, William R. Page, Jeremiah B. Workman
By
Geology, Minerals, Energy, and Geophysics Science Center

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
By
Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center

Digital Geologic Map of the Nevada Test Site and Vicinity, Nye, Lincoln, and Clark Counties, Nevada, and Inyo County, California

This digital geologic map of the Nevada Test Site (NTS) and vicinity, as well as its accompanying digital geophysical maps, are compiled at 1:100,000 scale. The map compilation presents new polygon (geologic map unit contacts), line (fault, fold axis, metamorphic isograd, dike, and caldera wall) and point (structural attitude) vector data for the NTS and vicinity, Nye, Lincoln, and Clark Counties,
Authors
Janet L. Slate, Margaret E. Berry, Peter D. Rowley, Christopher J. Fridrich, Karen S. Morgan, Jeremiah B. Workman, Owen D. Young, Gary L. Dixon, Van S. Williams, Edwin H. McKee, David A. Ponce, Thomas G. Hildenbrand, W. C. Swadley, Scott C. Lundstrom, E. Bartlett Ekren, Richard G. Warren, J. C. Cole, Robert J. Fleck, Marvin A. Lanphere, David A. Sawyer, Scott A. Minor, Daniel J. Grunwald, Randell J. Laczniak, Christopher M. Menges, James C. Yount, Angela S. Jayko

Preliminary geologic map of the Moapa West Quadrangle, Clark County, Nevada

No abstract available.
Authors
Dwight L. Schmidt, William R. Page, Jeremiah B. Workman

Evaluation of shorelines along Lake Mohave, Lake Mead National Recreation Area, Nevada and Arizona

The hdpw (head-in-a-pumping-well) program described in this report is a post-processor that calculates the head in a pumping well based on thesimulated head at a finite-difference model cell that contains the well. The calculations are based on the Thiem equation. The hdpw code works with the U.S. Geological Survey modular finite-difference ground-water flow model, which is commonly called MOD
Authors
Jeremiah B. Workman
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