Skip to main content
U.S. flag

An official website of the United States government

A. Kate Souders

Kate Souders is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.

Science and Products

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
plasma lab instruments

From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems

Project objectives are to (1) develop innovative analytical techniques for isotope geochemistry and U-Pb geochronology using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and (2) apply these techniques to collaborative research projects of high priority to the Mineral Resources Program, including studies related to the formation of "critical mineral" deposits, and...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems

Project objectives are to (1) develop innovative analytical techniques for isotope geochemistry and U-Pb geochronology using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and (2) apply these techniques to collaborative research projects of high priority to the Mineral Resources Program, including studies related to the formation of "critical mineral" deposits, and...
Learn More
link
USGS science for a changing world logo

Serving the U.S. Geological Survey’s geochronological data

Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This proj
By
Community for Data Integration (CDI)
link

Serving the U.S. Geological Survey’s geochronological data

Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This proj
Learn More

Data release of isotope geochemistry, mineral chemistry, and geochronology for a Proterozoic paragneiss sampled from drill core from North Dakota

This U.S. Geological Survey (USGS) data release provides whole rock isotope geochemistry, zircon hafnium isotope geochemistry, feldspar mineral chemistry, and zircon, monazite, and xenotime geochronology for a paragneiss sampled from a drill core from North Dakota. The sample was collected from the 9-11R E-M Larson well in order to constrain the depositional age, provenance, metamorphic history, a
By
Geology, Minerals, Energy, and Geophysics Science Center

Zircon U-Pb data for Proterozoic rocks in southwestern Colorado and rocks from drill core from Wyoming, Montana, and Nebraska

This U.S. Geological Survey (USGS) data release provides U-Pb zircon data and geochronology for Proterozoic rocks in the Needle Mountains of southwestern Colorado and for Proterozoic rocks sampled from drill cores from Wyoming, Montana, and Nebraska. Samples from the Needle Mountains were collected in order to constrain the polyphase tectonic evolution of the area. Drill core samples are part of a
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center

USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data (ver. 3.0, May 2024)

USGS Geochron is a database of geochronological and thermochronological dates and data. The data set contains published ages, dates, analytical information, sample metadata including location, and source citations. The following analytical techniques are represented in the data set: 40Ar/39Ar, K-Ar, U-Th-Pb, Sm-Nd, Rb-Sr, Lu-Hf, fission track, and luminescence. This data set incorporates data prev

By
Community for Data Integration (CDI), Geosciences and Environmental Change Science Center

Zircon U-Pb data for ash-fall tuffs and sandstones of the Cenozoic Amargosa Valley and Bat Mountain Formations exposed on Bat Mountain, southern Funeral Mountains, California, USA

This document includes two suites of zircon U-Pb data that establish a detailed chronostratigraphy for Cenozoic strata exposed on Bat Mountain of the southern Funeral Mountains, California, USA. The first suite of data includes detrital zircon U-Pb age distributions that characterize the maximum depositional age and provenance of five sandstone samples from the Oligocene-Miocene Amargosa Valley Fo
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

Geochemical and geochronologic evidence for a contiguous northeastern Wyoming Province

The extent and nature of the Wyoming Province, an Archean craton in southwestern Laurentia, are poorly understood due to limited exposure between spatially isolated basement-cored uplifts. This lack of exposure has led to debate about whether the northeastern Wyoming Province is underlain by contiguous Archean crust or Proterozoic rocks and suture zone associated with the Trans-Hudson orogeny. To
Authors
Ian William Hillenbrand, Amy K. Gilmer, Amanda (Kate) Souders, Ilya N. Bindeman
By
Geosciences and Environmental Change Science Center

Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen

The crustal evolution of the southernmost ∼2000–1800 Ma Trans-Hudson orogen (THO) is enigmatic due to burial by Phanerozoic sediments. We provide new insights through petrochronologic analysis of a paragneiss drill core sample. Detrital zircon age peaks at 2625, 2340, and 1880 Ma and Hf isotopes suggest Paleoproterozoic arc development proximal to Archean source(s). Phase equilibria modeling and t
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Amanda (Kate) Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
By
Geosciences and Environmental Change Science Center, Geology, Geophysics, and Geochemistry Science Center

Heterogeneous multi-stage accretionary orogenesis — Evidence from the Gunnison block in the Yavapai Province, southwest USA

Proterozoic rocks exposed in the southwestern U.S.A. represent one of the best examples of crustal growth by arc-related magmatism and accretionary orogenesis. Within the Southwest the 1.8–1.7 Ga Yavapai Province is widely regarded as a classic example of juvenile arc crust, however 1.8–2.5 Ga inherited zircon and Nd and Hf model ages have been recognized near Gunnison in central Colorado. These d
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Karl E. Karlstrom, Amanda (Kate) Souders, Jorge A. Vazquez, Wayne R. Premo
By
Geosciences and Environmental Change Science Center

Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA

The Proterozoic tectonic evolution of the south-western USA remains incompletely understood due to limited constraints on the timing and conditions of the tectono-metamorphic phases and depositional age of metasedimentary successions. We integrated multi-scale compositional mapping, petrologic modeling, and in situ geochronology to constrain pressure-temperature-time paths from samples of Paleopro
Authors
Ian William Hillenbrand, Michael L. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda (Kate) Souders
By
Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center

Revised age and regional correlations of Cenozoic strata on Bat Mountain, Death Valley region, California, USA, from zircon U-Pb geochronology of sandstones and ash-fall tuffs

Basin analysis and tectonic reconstructions of the Cenozoic history of the Death Valley region, California, USA, are hindered by a lack of volcanic (tuff) age control in many stratigraphic successions exposed in the Grapevine and Funeral Mountains of California, USA. Although maximum depositional ages (MDAs) interpreted from detrital zircon U-Pb data may be a promising alternative to volcanic ages
Authors
Theresa Maude Schwartz, Amanda (Kate) Souders, Jens-Erik Lundstern, Amy K. Gilmer, Ren A. Thompson
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

Postcaldera intrusive magmatism at the Platoro caldera complex, Southern Rocky Mountain volcanic field, Colorado, USA

The Oligocene Platoro caldera complex of the San Juan volcanic locus in Colorado (USA) features numerous exposed plutons both within the caldera and outside its margins, enabling investigation of the timing and evolution of postcaldera magmatism. Intrusion whole-rock geochemistry and phenocryst and/or mineral trace element compositions coupled with new zircon U-Pb geo-chronology and zircon in situ
Authors
Amy K. Gilmer, Ren A. Thompson, Peter W. Lipman, Jorge A. Vazquez, Amanda (Kate) Souders
By
National Cooperative Geologic Mapping Program, Volcano Hazards Program, Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center, Volcano Science Center

Evidence for a concealed Midcontinent Rift-related northeast Iowa intrusive complex

Large amplitude aeromagnetic and gravity anomalies over a ~9500 km2 area of northeast Iowa and southeast Minnesota have been interpreted to reflect the northeast Iowa intrusive complex (NEIIC), a buried intrusive igneous complex composed of mafic/ultramafic rocks in the Yavapai Province (1.8–1.7 Ga). Hundreds of meters of Paleozoic sedimentary cover and a paucity of basement drilling have prevente
Authors
Benjamin J. Drenth, A. Kate Souders, Klaus J. Schulz, Joshua M. Feinberg, Raymond R. Anderson, Val W. Chandler, William F. Cannon, Ryan Clark
By
Geology, Geophysics, and Geochemistry Science Center

Bayesian nitrate source apportionment to individual groundwater wells in the Central Valley by use of elemental and isotopic tracers

Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as in the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) in agricultural areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, and septic waste. Knowledge of the relative proportion that each of these so
Authors
Katherine M Ransom, Mark N. Grote, Amanda Deinhart, Gary Eppich, Carol Kendall, Matthew E. Sanborn, A. Kate Sounders, Joshua Wimpenny, Qing-zhu Yin, Megan B. Young, Thomas Harter
By
Water Resources Mission Area, Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program

Science and Products

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
plasma lab instruments

From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems

Project objectives are to (1) develop innovative analytical techniques for isotope geochemistry and U-Pb geochronology using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and (2) apply these techniques to collaborative research projects of high priority to the Mineral Resources Program, including studies related to the formation of "critical mineral" deposits, and...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

From Outcrop to Ions: development and application of in-situ isotope ratio measurements to solve geologic problems

Project objectives are to (1) develop innovative analytical techniques for isotope geochemistry and U-Pb geochronology using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and (2) apply these techniques to collaborative research projects of high priority to the Mineral Resources Program, including studies related to the formation of "critical mineral" deposits, and...
Learn More
link
USGS science for a changing world logo

Serving the U.S. Geological Survey’s geochronological data

Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This proj
By
Community for Data Integration (CDI)
link

Serving the U.S. Geological Survey’s geochronological data

Geochronological data provide essential information necessary for understanding the timing of geologic processes and events, as well as quantifying rates and timescales key to geologic mapping, mineral and energy resource and hazard assessments. The USGS’s National Geochronological Database (NGDB) contains over 30,000 radiometric ages, but no formal update has occurred in over 20 years. This proj
Learn More

Data release of isotope geochemistry, mineral chemistry, and geochronology for a Proterozoic paragneiss sampled from drill core from North Dakota

This U.S. Geological Survey (USGS) data release provides whole rock isotope geochemistry, zircon hafnium isotope geochemistry, feldspar mineral chemistry, and zircon, monazite, and xenotime geochronology for a paragneiss sampled from a drill core from North Dakota. The sample was collected from the 9-11R E-M Larson well in order to constrain the depositional age, provenance, metamorphic history, a
By
Geology, Minerals, Energy, and Geophysics Science Center

Zircon U-Pb data for Proterozoic rocks in southwestern Colorado and rocks from drill core from Wyoming, Montana, and Nebraska

This U.S. Geological Survey (USGS) data release provides U-Pb zircon data and geochronology for Proterozoic rocks in the Needle Mountains of southwestern Colorado and for Proterozoic rocks sampled from drill cores from Wyoming, Montana, and Nebraska. Samples from the Needle Mountains were collected in order to constrain the polyphase tectonic evolution of the area. Drill core samples are part of a
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center

USGS Geochron: A Database of Geochronological and Thermochronological Dates and Data (ver. 3.0, May 2024)

USGS Geochron is a database of geochronological and thermochronological dates and data. The data set contains published ages, dates, analytical information, sample metadata including location, and source citations. The following analytical techniques are represented in the data set: 40Ar/39Ar, K-Ar, U-Th-Pb, Sm-Nd, Rb-Sr, Lu-Hf, fission track, and luminescence. This data set incorporates data prev

By
Community for Data Integration (CDI), Geosciences and Environmental Change Science Center

Zircon U-Pb data for ash-fall tuffs and sandstones of the Cenozoic Amargosa Valley and Bat Mountain Formations exposed on Bat Mountain, southern Funeral Mountains, California, USA

This document includes two suites of zircon U-Pb data that establish a detailed chronostratigraphy for Cenozoic strata exposed on Bat Mountain of the southern Funeral Mountains, California, USA. The first suite of data includes detrital zircon U-Pb age distributions that characterize the maximum depositional age and provenance of five sandstone samples from the Oligocene-Miocene Amargosa Valley Fo
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

Geochemical and geochronologic evidence for a contiguous northeastern Wyoming Province

The extent and nature of the Wyoming Province, an Archean craton in southwestern Laurentia, are poorly understood due to limited exposure between spatially isolated basement-cored uplifts. This lack of exposure has led to debate about whether the northeastern Wyoming Province is underlain by contiguous Archean crust or Proterozoic rocks and suture zone associated with the Trans-Hudson orogeny. To
Authors
Ian William Hillenbrand, Amy K. Gilmer, Amanda (Kate) Souders, Ilya N. Bindeman
By
Geosciences and Environmental Change Science Center

Paleoproterozoic reworking of Archean crust and extreme back-arc metamorphism in the enigmatic southern Trans-Hudson orogen

The crustal evolution of the southernmost ∼2000–1800 Ma Trans-Hudson orogen (THO) is enigmatic due to burial by Phanerozoic sediments. We provide new insights through petrochronologic analysis of a paragneiss drill core sample. Detrital zircon age peaks at 2625, 2340, and 1880 Ma and Hf isotopes suggest Paleoproterozoic arc development proximal to Archean source(s). Phase equilibria modeling and t
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Amanda (Kate) Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
By
Geosciences and Environmental Change Science Center, Geology, Geophysics, and Geochemistry Science Center

Heterogeneous multi-stage accretionary orogenesis — Evidence from the Gunnison block in the Yavapai Province, southwest USA

Proterozoic rocks exposed in the southwestern U.S.A. represent one of the best examples of crustal growth by arc-related magmatism and accretionary orogenesis. Within the Southwest the 1.8–1.7 Ga Yavapai Province is widely regarded as a classic example of juvenile arc crust, however 1.8–2.5 Ga inherited zircon and Nd and Hf model ages have been recognized near Gunnison in central Colorado. These d
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael L. Williams, Karl E. Karlstrom, Amanda (Kate) Souders, Jorge A. Vazquez, Wayne R. Premo
By
Geosciences and Environmental Change Science Center

Monazite and xenotime petrochronologic constraints on four Proterozoic tectonic episodes and ca. 1705 Ma age of the Uncompahgre Formation, southwestern Colorado, USA

The Proterozoic tectonic evolution of the south-western USA remains incompletely understood due to limited constraints on the timing and conditions of the tectono-metamorphic phases and depositional age of metasedimentary successions. We integrated multi-scale compositional mapping, petrologic modeling, and in situ geochronology to constrain pressure-temperature-time paths from samples of Paleopro
Authors
Ian William Hillenbrand, Michael L. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda (Kate) Souders
By
Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center

Revised age and regional correlations of Cenozoic strata on Bat Mountain, Death Valley region, California, USA, from zircon U-Pb geochronology of sandstones and ash-fall tuffs

Basin analysis and tectonic reconstructions of the Cenozoic history of the Death Valley region, California, USA, are hindered by a lack of volcanic (tuff) age control in many stratigraphic successions exposed in the Grapevine and Funeral Mountains of California, USA. Although maximum depositional ages (MDAs) interpreted from detrital zircon U-Pb data may be a promising alternative to volcanic ages
Authors
Theresa Maude Schwartz, Amanda (Kate) Souders, Jens-Erik Lundstern, Amy K. Gilmer, Ren A. Thompson
By
National Cooperative Geologic Mapping Program, Geosciences and Environmental Change Science Center

Postcaldera intrusive magmatism at the Platoro caldera complex, Southern Rocky Mountain volcanic field, Colorado, USA

The Oligocene Platoro caldera complex of the San Juan volcanic locus in Colorado (USA) features numerous exposed plutons both within the caldera and outside its margins, enabling investigation of the timing and evolution of postcaldera magmatism. Intrusion whole-rock geochemistry and phenocryst and/or mineral trace element compositions coupled with new zircon U-Pb geo-chronology and zircon in situ
Authors
Amy K. Gilmer, Ren A. Thompson, Peter W. Lipman, Jorge A. Vazquez, Amanda (Kate) Souders
By
National Cooperative Geologic Mapping Program, Volcano Hazards Program, Geology, Geophysics, and Geochemistry Science Center, Geosciences and Environmental Change Science Center, Volcano Science Center

Evidence for a concealed Midcontinent Rift-related northeast Iowa intrusive complex

Large amplitude aeromagnetic and gravity anomalies over a ~9500 km2 area of northeast Iowa and southeast Minnesota have been interpreted to reflect the northeast Iowa intrusive complex (NEIIC), a buried intrusive igneous complex composed of mafic/ultramafic rocks in the Yavapai Province (1.8–1.7 Ga). Hundreds of meters of Paleozoic sedimentary cover and a paucity of basement drilling have prevente
Authors
Benjamin J. Drenth, A. Kate Souders, Klaus J. Schulz, Joshua M. Feinberg, Raymond R. Anderson, Val W. Chandler, William F. Cannon, Ryan Clark
By
Geology, Geophysics, and Geochemistry Science Center

Bayesian nitrate source apportionment to individual groundwater wells in the Central Valley by use of elemental and isotopic tracers

Groundwater quality is a concern in alluvial aquifers that underlie agricultural areas, such as in the San Joaquin Valley of California. Shallow domestic wells (less than 150 m deep) in agricultural areas are often contaminated by nitrate. Agricultural and rural nitrate sources include dairy manure, synthetic fertilizers, and septic waste. Knowledge of the relative proportion that each of these so
Authors
Katherine M Ransom, Mark N. Grote, Amanda Deinhart, Gary Eppich, Carol Kendall, Matthew E. Sanborn, A. Kate Sounders, Joshua Wimpenny, Qing-zhu Yin, Megan B. Young, Thomas Harter
By
Water Resources Mission Area, Ecosystems Mission Area, Toxic Substances Hydrology, Environmental Health Program
Was this page helpful?