A. Kate Souders
Kate Souders is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Igneous and Metamorphic Working Group
The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West (IMW) Project by conducting geologic mapping in igneous terranes and research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West region and their implications for mineral resource exploration and tectonic history. This research provides a process-based...
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...
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...
LA-MC-ICP-MS Hf isotopes in zircons from the Mountain Pass Intrusive Suite, California
This U.S. Geological Survey (USGS) data release accompanies planned publication ‘Geochemistry and radiogenic isotopes constrain the mantle source region of the Mountain Pass Intrusive Suite, California' and planned data release 'Whole-rock geochemical and isotopic data for the Mountain Pass Intrusive Suite, California'. The data release includes laser ablation multi-collector inductively...
LA-ICP-MS U-Pb Geochronology Data for Igneous Rocks Constraining the Timing of the Great Lakes tectonic zone, central Upper Peninsula, Michigan, USA
This U.S. Geological Survey (USGS) data release accompanies planned publication ‘New constraints on location and timing of the Great Lakes tectonic zone, central Upper Peninsula, Michigan, USA. The data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb zircon data and/or U-Pb apatite data for two samples from the Upper Peninsula, Michigan, USA...
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...
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...
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...
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...
In situ Re-Os geochronology of Re-rich Palaeogene molybdenite by LA-ICP-MS/MS
In situ Re–Os geochronology by LA-ICP-MS/MS was previously demonstrated by reacting Os with CH4 or N2O reaction gasses. However, for both reactions, a minor proportion of the Re parent isotope also reacts, potentially leading to significant isobaric interferences of 187Re on 187Os, especially for young samples with little radiogenic in-growth. Here we present an interlaboratory...
Authors
Stijm Glorie, Jay Michael Thompson, Sarah E. Gilbert, Amanda (Kate) Souders
Accuracy and precision of U–Pb zircon geochronology at high spatial resolution (7–20 μm spots) by laser ablation-ICP-single-collector-sector-field-mass spectrometry
Use of small spots (≤20µm) for laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology is of increasing interest in the Earth sciences because the temporal record of geologic processes is often preserved on a fine-scale within zircon grains. However the systematic biases and external sources of uncertainity of U-Pb ages is poorly defined when...
Authors
Pulok K. Mukherjee, Amanda (Kate) Souders, Paul J. Sylvester
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Amanda (Kate) Souders, Ilya N. Bindeman
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael S. Williams, Amanda (Kate) Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael S. Williams, Karl E. Karlstrom, Amanda (Kate) Souders, Jorge A. Vazquez, Wayne R. Premo
Geophysical architecture of the Neoarchean Mentor anorthosite intrusive complex, northwestern Minnesota
The ca. 2737 Ma (Souders, 2023) Mentor anorthosite intrusive complex (MAIC) lies near the northern margin of the Wawa subprovince of the Archean Superior Province, in an area of northwestern Minnesota where the Wawa, Quetico, and Wabigoon subprovinces are juxtaposed in close proximity (Fig. 1). The rocks of interest are entirely concealed by 10s to >100 m of unconsolidated Quaternary...
Authors
Benjamin J. Drenth, Amy Radakovich Block, George J. Hudak, Amanda (Kate) Souders, Stacy Saari
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...
Authors
Ian William Hillenbrand, Michael S. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda (Kate) Souders
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...
Authors
Theresa Maude Schwartz, Amanda (Kate) Souders, Jens-Erik Lundstern, Amy K. Gilmer, Ren A. Thompson
Significance of U-Pb detrital zircon geochronology for mudstone provenance
Detrital zircon U-Pb studies of mudstone provenance are rare but may preferentially fingerprint distal zircon sources. To examine this issue, Pierre Shale and Trinidad Sandstone deposited in a Late Cretaceous deltaic environment in the Raton Basin, Colorado (USA), were measured for detrital zircon U-Pb age by laser ablation–inductively coupled plasma–mass spectrometry. Two major detrital...
Authors
Paul Sylvester, Amanda (Kate) Souders, Rui Liu
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...
Authors
Amy K. Gilmer, Ren A. Thompson, Peter W. Lipman, Jorge A. Vazquez, Amanda (Kate) Souders
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...
Authors
Benjamin J. Drenth, Amanda (Kate) Souders, Klaus J. Schulz, Joshua M. Feinberg, Raymond R. Anderson, Val W. Chandler, William F. Cannon, Ryan Clark
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...
Authors
Katherine Marie Ransom, Mark N. Grote, Amanda Deinhart, Gary Eppich, Carol Kendall, Matthew E. Sanborn, Amanda (Kate) Souders, Joshua Wimpenny, Qing-zhu Yin, Megan B. Young, Thomas Harter
Science and Products
Igneous and Metamorphic Working Group
The Igneous and Metamorphic Working Group supports the Geologic Framework of the Intermountain West (IMW) Project by conducting geologic mapping in igneous terranes and research focused on understanding the magmatic and metamorphic processes that shaped the Intermountain West region and their implications for mineral resource exploration and tectonic history. This research provides a process-based...
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...
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...
LA-MC-ICP-MS Hf isotopes in zircons from the Mountain Pass Intrusive Suite, California
This U.S. Geological Survey (USGS) data release accompanies planned publication ‘Geochemistry and radiogenic isotopes constrain the mantle source region of the Mountain Pass Intrusive Suite, California' and planned data release 'Whole-rock geochemical and isotopic data for the Mountain Pass Intrusive Suite, California'. The data release includes laser ablation multi-collector inductively...
LA-ICP-MS U-Pb Geochronology Data for Igneous Rocks Constraining the Timing of the Great Lakes tectonic zone, central Upper Peninsula, Michigan, USA
This U.S. Geological Survey (USGS) data release accompanies planned publication ‘New constraints on location and timing of the Great Lakes tectonic zone, central Upper Peninsula, Michigan, USA. The data release includes laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb zircon data and/or U-Pb apatite data for two samples from the Upper Peninsula, Michigan, USA...
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...
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...
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...
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...
In situ Re-Os geochronology of Re-rich Palaeogene molybdenite by LA-ICP-MS/MS
In situ Re–Os geochronology by LA-ICP-MS/MS was previously demonstrated by reacting Os with CH4 or N2O reaction gasses. However, for both reactions, a minor proportion of the Re parent isotope also reacts, potentially leading to significant isobaric interferences of 187Re on 187Os, especially for young samples with little radiogenic in-growth. Here we present an interlaboratory...
Authors
Stijm Glorie, Jay Michael Thompson, Sarah E. Gilbert, Amanda (Kate) Souders
Accuracy and precision of U–Pb zircon geochronology at high spatial resolution (7–20 μm spots) by laser ablation-ICP-single-collector-sector-field-mass spectrometry
Use of small spots (≤20µm) for laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) U-Pb zircon geochronology is of increasing interest in the Earth sciences because the temporal record of geologic processes is often preserved on a fine-scale within zircon grains. However the systematic biases and external sources of uncertainity of U-Pb ages is poorly defined when...
Authors
Pulok K. Mukherjee, Amanda (Kate) Souders, Paul J. Sylvester
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Amanda (Kate) Souders, Ilya N. Bindeman
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael S. Williams, Amanda (Kate) Souders, Michael J. Jercinovic, Heather A. Lowers, Jorge A. Vazquez
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...
Authors
Ian William Hillenbrand, Amy K. Gilmer, Michael S. Williams, Karl E. Karlstrom, Amanda (Kate) Souders, Jorge A. Vazquez, Wayne R. Premo
Geophysical architecture of the Neoarchean Mentor anorthosite intrusive complex, northwestern Minnesota
The ca. 2737 Ma (Souders, 2023) Mentor anorthosite intrusive complex (MAIC) lies near the northern margin of the Wawa subprovince of the Archean Superior Province, in an area of northwestern Minnesota where the Wawa, Quetico, and Wabigoon subprovinces are juxtaposed in close proximity (Fig. 1). The rocks of interest are entirely concealed by 10s to >100 m of unconsolidated Quaternary...
Authors
Benjamin J. Drenth, Amy Radakovich Block, George J. Hudak, Amanda (Kate) Souders, Stacy Saari
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...
Authors
Ian William Hillenbrand, Michael S. Williams, Karl E. Karlstrom, Amy K. Gilmer, Heather A. Lowers, Michael J. Jercinovic, Kaitlyn Suarez, Amanda (Kate) Souders
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...
Authors
Theresa Maude Schwartz, Amanda (Kate) Souders, Jens-Erik Lundstern, Amy K. Gilmer, Ren A. Thompson
Significance of U-Pb detrital zircon geochronology for mudstone provenance
Detrital zircon U-Pb studies of mudstone provenance are rare but may preferentially fingerprint distal zircon sources. To examine this issue, Pierre Shale and Trinidad Sandstone deposited in a Late Cretaceous deltaic environment in the Raton Basin, Colorado (USA), were measured for detrital zircon U-Pb age by laser ablation–inductively coupled plasma–mass spectrometry. Two major detrital...
Authors
Paul Sylvester, Amanda (Kate) Souders, Rui Liu
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...
Authors
Amy K. Gilmer, Ren A. Thompson, Peter W. Lipman, Jorge A. Vazquez, Amanda (Kate) Souders
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...
Authors
Benjamin J. Drenth, Amanda (Kate) Souders, Klaus J. Schulz, Joshua M. Feinberg, Raymond R. Anderson, Val W. Chandler, William F. Cannon, Ryan Clark
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...
Authors
Katherine Marie Ransom, Mark N. Grote, Amanda Deinhart, Gary Eppich, Carol Kendall, Matthew E. Sanborn, Amanda (Kate) Souders, Joshua Wimpenny, Qing-zhu Yin, Megan B. Young, Thomas Harter