Karen Duttweiler Kelley
Karen Kelley is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.
Science and Products
Critical Minerals Mapping Initiative (CMMI)
The USGS, in combination with Geoscience Australia and the Geological Survey of Canada, formed the Critical Minerals Mapping Initiative (CMMI) in 2019 to combine expertise and collaboratively conduct research on critical mineral resources.
Tellurium in Igneous-related Epithermal Precious Metal Deposits in Colorado and New Mexico
The project aims to improve our understanding of the causes of tellurium enrichment in epithermal precious metal deposits, and strengthen our ability to assess the Nation's tellurium deposits. Tellurium is used in solar panel technologies and is considered a critical mineral. Epithermal deposits of this type represent a prospective future source of tellurium.
Critical Metals in Black Shales
Project objectives were to improve the understanding of critical mineral enrichment in black shales and improve accuracy of resource assessments.
Filter Total Items: 14
National-Scale Geophysical, Geologic, and Mineral Resource Data and Grids for the United States, Canada, and Australia: Data in Support of the Tri-National Critical Minerals Mapping Initiative
National-scale geologic, geophysical, and mineral resource raster and vector data covering the United States, Canada, and Australia are provided in this data release.
The data were compiled as part of the tri-national Critical Minerals Mapping Initiative (CMMI). The CMMI, established in 2019, is an international science collaboration between the U.S. Geological Survey (USGS), Geoscience Australi
Geochemical data for stream water samples from streams around the Pogo Deposit and Black Mountain Au occurrences, Big Delta quadrangle, Alaska, 2021
This data release is the result of a hydrogeochemical sampling campaign during summer 2021 to investigate whether high resolution geochemical analysis of waters for element chemistry can be used as an exploration tool for identifying gold-rich occurrences in parts of the Big Delta B-1 and B-2 quadrangles, within the Yukon-Tanana Upland region, Alaska. Historical USGS conventional stream sediment g
HySpex by NEO VNIR-1800 and SWIR-384 imaging spectrometer radiance and reflectance data, with associated ASD FieldSpec® NG calibration data, collected at Cripple Creek Victor mine, Cripple Creek, Colorado, 2017
HySpex by NEO (HySpex) VNIR-1800 and SWIR-384 imaging spectrometer radiance data were acquired on September 14, 2017 at the Cresson Pit of the Cripple Creek & Victor mine in Cripple Creek, Colorado. ASD FieldSpec® NG data were collected on September 13 and 14, 2017 at two calibration sites within the Cresson Pit imaged with the HySpex imaging spectrometers. The HySpex VNIR-1800 imaging spectromete
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) geochemical data for apatite grains in rocks and stream sediments from the Taurus porphyry copper deposit area, eastern Tanacross quadrangle, Alaska
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of apatite provide trace element concentrations that support indicator mineral studies near the Taurus porphyry Cu-Mo deposit in the eastern Tanacross quadrangle, Alaska. The Taurus deposit and others in the region are mostly concealed, and traditional stream sediment samples typically show subdued geochemical signatu
Geochemical data for alkaline igneous rock units in the Cripple Creek district, Colorado USA: 1989-2016
This data release includes new major and trace element geochemical data acquired by the U.S. Geological Survey (USGS) for igneous rocks in the Cripple Creek district in Colorado. Cripple Creek is among the largest epithermal districts in the world, with more than 800 metric tons (t) Au (less than 26.4 Moz). The ores are associated spatially, temporally, and genetically with ~34 to 28 Ma alkaline i
Geochemical data for stream water and stream sediment samples from the northeast part of the Tanacross quadrangle, Alaska
This data release is part of a study designed to test geochemical methods that best delineate known mineral deposits in the northeast part of the Tanacross 1 x 3 quadrangle, within the Yukon-Tanana Upland region, Alaska. The total area sampled is about 3,200 km2. Extensive tundra cover and patchy spruce/alder vegetation and very limited outcrop exposure characterize the area. Soils and stream sedi
Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska
The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral studies inclu
Data from the Chemical Analysis of Archived Stream-Sediment Samples, Alaska
This data release contains the elemental concentration data for more than 1700 archived stream-sediment samples collected in Alaska. Samples were retrieved from the USGS Mineral Program's sample archive in Denver, CO, and the Alaska Division of Geological and Geophysical Surveys Geologic Materials Center in Anchorage, AK. All samples were analyzed using a multi-element analytical method involving
Data and analysis for GIS-based identification of areas that have resource potential for sediment-hosted Pb-Zn deposits in Alaska
This data release contains the analytical results of a spatial analyses for the resource potential of sediment-hosted Pb-Zn (lead-zinc) deposits in the state of Alaska. Sediment-hosted Pb-Zn deposits in Alaska include those contained in carbonate rock and in clastic-dominated sequences. The geographic information system (GIS) analysis queried three publicly available statewide datasets in areas de
Corescan Hyperspectral Core Imager, Mark III system data collected for the characterization of mineral resources near Nabesna, Alaska, 2014-2016
Corescan Hyperspectral Core Imager Mark III (HCI-III) system data were acquired for hand samples, and subsequent billets made from the hand samples, collected during the U.S. Geological Survey (USGS) 2014, 2015, and 2016 field seasons in the Nabesna area of the eastern Alaska Range. This area contains exposed porphyry deposits and hand samples were collected throughout the region in support of the
Imaging spectrometer reflectance data, mineral predominance map, and white mica wavelength position map, Nabesna Quadrangle, Alaska
Approximately 1,900 square kilometers of imagery were collected from July 14 to July 21, 2014 using a HyMap sensor (Cocks and others, 1998) mounted on a modified Piper Navajo aircraft. The survey area covered parts of the Wrangell and Nutzotin Mountains in the eastern Alaska Range near Nabesna, Alaska. The aircraft was flown at an altitude of approximately 5,050 meters (m) (3,480 m above the mean
Whole rock, soil, sediment, x-ray diffraction, and electron microprobe analyses of samples from the Orange Hill-Bond Creek area, Nabesna Quadrangle, Alaska
This data release includes geochemical, x-ray diffraction mineralogical, and electron probe microanalysis (EPMA) data on rocks, soils, and sediments collected near the Orange Hill and Bond Creek porphyry copper deposits, Nabesna quadrangle, Alaska. Geochemical analyses were completed by a laboratory under contract with the U.S. Geological Survey (USGS). Electron microprobe and x-ray diffraction mi
Filter Total Items: 84
Critical minerals: Germanium and cobalt in the Bornite deposit, southwestern Brooks Range, Alaska
Increasing demand for Ge and Co has led to a renewed interest and focus on advancing our understanding of the occurrence, distribution, and sequestration of these critical elements in known ore deposits. A workflow using a variety of analytical techniques and co-registered datasets has been developed and was applied to the carbonate hosted Bornite Cu-Co (Zn,-Ge) deposit in Alaska, where a new oreb
Authors
Katharina Pfaff, Garth E. Graham, Alex Jones, Karen D. Kelley
Results of automated scanning electron microscope (SEM) analyses of rock and stream sediment samples from the Taurus porphyry copper deposit area, Tanacross quadrangle, eastern Alaska
Numerous porphyry copper-molybdenum-gold and epithermal deposits define a belt that extends from Eastern Alaska to western Yukon, Canada. An orientation study conducted near the Taurus porphyry deposit was designed to test methods that require minimal sample collection, preparation, and analytical time to determine the viability of indicator mineral studies as a reconnaissance exploration method.
Authors
Karen D. Kelley, Katharina Pfaff, Garth E. Graham
Data-driven prospectivity modelling of sediment-hosted Zn-Pb mineral systems and their critical raw materials
Demand for critical raw materials is expected to accelerate over the next few decades due to continued population growth and the shifting consumption patterns of the global economy. Sedimentary basins are important sources for critical raw materials and new discoveries of sediment–hosted Mississippi Valley–type (MVT) and/or clastic–dominated (CD) Zn–Pb deposits are likely required to mitigate futu
Authors
Christopher J. M. Lawley, Anne E. McCafferty, Garth E. Graham, David L. Huston, Karen D. Kelley, Karol Czarnota, Suzanne Paradis, Jan M. Peter, Nathan Hayward, Mike Barlow, Poul Emsbo, Joshua Aaron Coyan, Carma A. San Juan, Michael G. Gadd
Chemical analysis of archived stream-sediment samples, Alaska
Geochemical data are presented for more than 1,500 archived stream-sediment samples and accompanying quality control samples. The archived sediments were reanalyzed to improve the stream geochemical dataset for Alaska and to support ongoing U.S. Geological Survey (USGS) studies. Sediment samples were primarily from the USGS Mineral Resources Program’s sample archive in Denver, Colorado, but a few
Authors
Bronwen Wang, George N. D. Case, Mathew Granitto, Keith A. Labay, Nora B. Shew, Andrew D. Ingraham, Jaime S. Azain, Zachary C. Bueghly, Susan M. Karl, Karen D. Kelley
GIS-based identification of areas that have resource potential for sediment-hosted Pb-Zn deposits in Alaska
A state-wide Geographic Information System analysis was conducted to assess prospectivity for lead (Pb) and zinc (Zn) in sediment-hosted deposits in Alaska. The datasets that were utilized include publicly available geospatial datasets of lithologic, geochemical, and mineral occurrence data. Key characteristics of Pb-Zn deposits were identified in available datasets and scored with respect to rela
Authors
Karen D. Kelley, Garth E. Graham, Keith A. Labay, Nora B. Shew
USGS 2020 critical minerals review
Concerns about the lack of domestic production and availability of essential mineral raw materials were a recurring theme throughout the 20th century, particularly in the periods around armed conflicts (Congressional Research Service, 2019). These concerns resulted in the designation of particular minerals as “strategic” or “critical,” terms that commonly depend on the perspective of the user, but
Authors
Steven M. Fortier, Nedal T. Nassar, Karen D. Kelley, Graham W. Lederer, Jeffrey L. Mauk, Jane M. Hammarstrom, Warren C. Day, Robert R. Seal
Toward an effective global green economy: The Critical Minerals Mapping Initiative (CMMI)
Global population growth, economic development and the accelerating pace of technological innovation are driving increased demand for non-fuel mineral commodities that are vital for emerging and low-carbon technologies. Examples of such commodities include cobalt and graphite for rechargeable batteries, tellurium in thin-film solar photovoltaics and rare earth elements (REE) in permanent magnets,
Authors
Karen D. Kelley, David Huston, Jan Peter
Tectonic and magmatic controls on the metallogenesis of porphyry deposits in Alaska
Porphyry Cu and Mo deposits and occurrences are found throughout Alaska; they formed episodically during repeated subduction and arc-continent collisions spanning the Silurian to Quaternary. Porphyry systems occur in continental-margin and island arcs, which are broadly grouped into pre-accretionary or post-accretionary arcs. Pre-Mesozoic occurrences formed in continental or island arcs prior to a
Authors
Douglas C. Kreiner, James V. Jones, Karen D. Kelley, Garth E. Graham
Alkalic-type epithermal gold deposit model
This report summarizes the primary characteristics of alkalic-type epithermal gold (Au) deposits and provides an updated descriptive model. These deposits, primarily of Mesozoic to Neogene age, are among the largest epithermal gold deposits in the world. Considered a subset of low-sulfidation epithermal deposits, they are spatially and genetically linked to small stocks or clusters of intrusions c
Authors
Karen D. Kelley, Paul G. Spry, Virginia T. McLemore, David L. Fey, Eric D. Anderson
Hydrogeochemistry in the Yukon-Tanana Upland region of east-central Alaska: Possible exploration tool for porphyry-style deposits
A hydrogeochemical study using high resolution ICP-MS was undertaken at the Taurus and other porphyry Cu-Mo(-Au) occurrences and Ag-Au-Cu (+/- Pb, Zn) occurrences with epithermal-style characteristics in the Yukon-Tanana upland region of eastern Alaska. Surface water samples were collected from 30 sites on creeks that drain known deposits and occurrences and surrounding presumably unmineralized ar
Authors
Karen D. Kelley, Garth E. Graham
International geoscience collaboration to support critical mineral discovery
The importance of critical minerals and the need to expand and diversify critical mineral supply chains has been endorsed by the Federal governments of Australia, Canada, and the United States. The geoscience organizations of Geoscience Australia, the Geological Survey of Canada and the U.S. Geological Survey have created the Critical Minerals Mapping Initiative to build a diversified critical min
Authors
, ,
Evaluation of the analytical methods used to determine the elemental concentrations found in the stream geochemical dataset compiled for Alaska
A recent U.S. Geological Survey data compilation of stream-sediment geochemistry for Alaska contains decades of analyses collected under numerous Federal and State programs. The compiled data were determined by various analytical methods. Some samples were reanalyzed by a different analytical method than the original, resulting in some elements having concentrations reported by multiple analytical
Authors
Bronwen Wang, Karl J. Ellefsen, Matthew Granitto, Karen D. Kelley, Susan M. Karl, George N. D. Case, Douglas C. Kreiner, Courtney L. Amundson
Science and Products
Critical Minerals Mapping Initiative (CMMI)
The USGS, in combination with Geoscience Australia and the Geological Survey of Canada, formed the Critical Minerals Mapping Initiative (CMMI) in 2019 to combine expertise and collaboratively conduct research on critical mineral resources.
Tellurium in Igneous-related Epithermal Precious Metal Deposits in Colorado and New Mexico
The project aims to improve our understanding of the causes of tellurium enrichment in epithermal precious metal deposits, and strengthen our ability to assess the Nation's tellurium deposits. Tellurium is used in solar panel technologies and is considered a critical mineral. Epithermal deposits of this type represent a prospective future source of tellurium.
Critical Metals in Black Shales
Project objectives were to improve the understanding of critical mineral enrichment in black shales and improve accuracy of resource assessments.
Filter Total Items: 14
National-Scale Geophysical, Geologic, and Mineral Resource Data and Grids for the United States, Canada, and Australia: Data in Support of the Tri-National Critical Minerals Mapping Initiative
National-scale geologic, geophysical, and mineral resource raster and vector data covering the United States, Canada, and Australia are provided in this data release.
The data were compiled as part of the tri-national Critical Minerals Mapping Initiative (CMMI). The CMMI, established in 2019, is an international science collaboration between the U.S. Geological Survey (USGS), Geoscience Australi
Geochemical data for stream water samples from streams around the Pogo Deposit and Black Mountain Au occurrences, Big Delta quadrangle, Alaska, 2021
This data release is the result of a hydrogeochemical sampling campaign during summer 2021 to investigate whether high resolution geochemical analysis of waters for element chemistry can be used as an exploration tool for identifying gold-rich occurrences in parts of the Big Delta B-1 and B-2 quadrangles, within the Yukon-Tanana Upland region, Alaska. Historical USGS conventional stream sediment g
HySpex by NEO VNIR-1800 and SWIR-384 imaging spectrometer radiance and reflectance data, with associated ASD FieldSpec® NG calibration data, collected at Cripple Creek Victor mine, Cripple Creek, Colorado, 2017
HySpex by NEO (HySpex) VNIR-1800 and SWIR-384 imaging spectrometer radiance data were acquired on September 14, 2017 at the Cresson Pit of the Cripple Creek & Victor mine in Cripple Creek, Colorado. ASD FieldSpec® NG data were collected on September 13 and 14, 2017 at two calibration sites within the Cresson Pit imaged with the HySpex imaging spectrometers. The HySpex VNIR-1800 imaging spectromete
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) geochemical data for apatite grains in rocks and stream sediments from the Taurus porphyry copper deposit area, eastern Tanacross quadrangle, Alaska
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of apatite provide trace element concentrations that support indicator mineral studies near the Taurus porphyry Cu-Mo deposit in the eastern Tanacross quadrangle, Alaska. The Taurus deposit and others in the region are mostly concealed, and traditional stream sediment samples typically show subdued geochemical signatu
Geochemical data for alkaline igneous rock units in the Cripple Creek district, Colorado USA: 1989-2016
This data release includes new major and trace element geochemical data acquired by the U.S. Geological Survey (USGS) for igneous rocks in the Cripple Creek district in Colorado. Cripple Creek is among the largest epithermal districts in the world, with more than 800 metric tons (t) Au (less than 26.4 Moz). The ores are associated spatially, temporally, and genetically with ~34 to 28 Ma alkaline i
Geochemical data for stream water and stream sediment samples from the northeast part of the Tanacross quadrangle, Alaska
This data release is part of a study designed to test geochemical methods that best delineate known mineral deposits in the northeast part of the Tanacross 1 x 3 quadrangle, within the Yukon-Tanana Upland region, Alaska. The total area sampled is about 3,200 km2. Extensive tundra cover and patchy spruce/alder vegetation and very limited outcrop exposure characterize the area. Soils and stream sedi
Electron Probe Microanalyses of apatite, rutile, and titanite from stream sediment and rock samples in the eastern Tanacross quadrangle, eastern Alaska
The exploration for porphyry deposits in some parts of Alaska may require unconventional exploration geochemical methods, depending on type of cover. The Taurus deposit and others in the region are mostly concealed by residual soils that in part include ash and loess, and therefore traditional stream sediment samples typically contain subdued geochemical signatures. Indicator mineral studies inclu
Data from the Chemical Analysis of Archived Stream-Sediment Samples, Alaska
This data release contains the elemental concentration data for more than 1700 archived stream-sediment samples collected in Alaska. Samples were retrieved from the USGS Mineral Program's sample archive in Denver, CO, and the Alaska Division of Geological and Geophysical Surveys Geologic Materials Center in Anchorage, AK. All samples were analyzed using a multi-element analytical method involving
Data and analysis for GIS-based identification of areas that have resource potential for sediment-hosted Pb-Zn deposits in Alaska
This data release contains the analytical results of a spatial analyses for the resource potential of sediment-hosted Pb-Zn (lead-zinc) deposits in the state of Alaska. Sediment-hosted Pb-Zn deposits in Alaska include those contained in carbonate rock and in clastic-dominated sequences. The geographic information system (GIS) analysis queried three publicly available statewide datasets in areas de
Corescan Hyperspectral Core Imager, Mark III system data collected for the characterization of mineral resources near Nabesna, Alaska, 2014-2016
Corescan Hyperspectral Core Imager Mark III (HCI-III) system data were acquired for hand samples, and subsequent billets made from the hand samples, collected during the U.S. Geological Survey (USGS) 2014, 2015, and 2016 field seasons in the Nabesna area of the eastern Alaska Range. This area contains exposed porphyry deposits and hand samples were collected throughout the region in support of the
Imaging spectrometer reflectance data, mineral predominance map, and white mica wavelength position map, Nabesna Quadrangle, Alaska
Approximately 1,900 square kilometers of imagery were collected from July 14 to July 21, 2014 using a HyMap sensor (Cocks and others, 1998) mounted on a modified Piper Navajo aircraft. The survey area covered parts of the Wrangell and Nutzotin Mountains in the eastern Alaska Range near Nabesna, Alaska. The aircraft was flown at an altitude of approximately 5,050 meters (m) (3,480 m above the mean
Whole rock, soil, sediment, x-ray diffraction, and electron microprobe analyses of samples from the Orange Hill-Bond Creek area, Nabesna Quadrangle, Alaska
This data release includes geochemical, x-ray diffraction mineralogical, and electron probe microanalysis (EPMA) data on rocks, soils, and sediments collected near the Orange Hill and Bond Creek porphyry copper deposits, Nabesna quadrangle, Alaska. Geochemical analyses were completed by a laboratory under contract with the U.S. Geological Survey (USGS). Electron microprobe and x-ray diffraction mi
Filter Total Items: 84
Critical minerals: Germanium and cobalt in the Bornite deposit, southwestern Brooks Range, Alaska
Increasing demand for Ge and Co has led to a renewed interest and focus on advancing our understanding of the occurrence, distribution, and sequestration of these critical elements in known ore deposits. A workflow using a variety of analytical techniques and co-registered datasets has been developed and was applied to the carbonate hosted Bornite Cu-Co (Zn,-Ge) deposit in Alaska, where a new oreb
Authors
Katharina Pfaff, Garth E. Graham, Alex Jones, Karen D. Kelley
Results of automated scanning electron microscope (SEM) analyses of rock and stream sediment samples from the Taurus porphyry copper deposit area, Tanacross quadrangle, eastern Alaska
Numerous porphyry copper-molybdenum-gold and epithermal deposits define a belt that extends from Eastern Alaska to western Yukon, Canada. An orientation study conducted near the Taurus porphyry deposit was designed to test methods that require minimal sample collection, preparation, and analytical time to determine the viability of indicator mineral studies as a reconnaissance exploration method.
Authors
Karen D. Kelley, Katharina Pfaff, Garth E. Graham
Data-driven prospectivity modelling of sediment-hosted Zn-Pb mineral systems and their critical raw materials
Demand for critical raw materials is expected to accelerate over the next few decades due to continued population growth and the shifting consumption patterns of the global economy. Sedimentary basins are important sources for critical raw materials and new discoveries of sediment–hosted Mississippi Valley–type (MVT) and/or clastic–dominated (CD) Zn–Pb deposits are likely required to mitigate futu
Authors
Christopher J. M. Lawley, Anne E. McCafferty, Garth E. Graham, David L. Huston, Karen D. Kelley, Karol Czarnota, Suzanne Paradis, Jan M. Peter, Nathan Hayward, Mike Barlow, Poul Emsbo, Joshua Aaron Coyan, Carma A. San Juan, Michael G. Gadd
Chemical analysis of archived stream-sediment samples, Alaska
Geochemical data are presented for more than 1,500 archived stream-sediment samples and accompanying quality control samples. The archived sediments were reanalyzed to improve the stream geochemical dataset for Alaska and to support ongoing U.S. Geological Survey (USGS) studies. Sediment samples were primarily from the USGS Mineral Resources Program’s sample archive in Denver, Colorado, but a few
Authors
Bronwen Wang, George N. D. Case, Mathew Granitto, Keith A. Labay, Nora B. Shew, Andrew D. Ingraham, Jaime S. Azain, Zachary C. Bueghly, Susan M. Karl, Karen D. Kelley
GIS-based identification of areas that have resource potential for sediment-hosted Pb-Zn deposits in Alaska
A state-wide Geographic Information System analysis was conducted to assess prospectivity for lead (Pb) and zinc (Zn) in sediment-hosted deposits in Alaska. The datasets that were utilized include publicly available geospatial datasets of lithologic, geochemical, and mineral occurrence data. Key characteristics of Pb-Zn deposits were identified in available datasets and scored with respect to rela
Authors
Karen D. Kelley, Garth E. Graham, Keith A. Labay, Nora B. Shew
USGS 2020 critical minerals review
Concerns about the lack of domestic production and availability of essential mineral raw materials were a recurring theme throughout the 20th century, particularly in the periods around armed conflicts (Congressional Research Service, 2019). These concerns resulted in the designation of particular minerals as “strategic” or “critical,” terms that commonly depend on the perspective of the user, but
Authors
Steven M. Fortier, Nedal T. Nassar, Karen D. Kelley, Graham W. Lederer, Jeffrey L. Mauk, Jane M. Hammarstrom, Warren C. Day, Robert R. Seal
Toward an effective global green economy: The Critical Minerals Mapping Initiative (CMMI)
Global population growth, economic development and the accelerating pace of technological innovation are driving increased demand for non-fuel mineral commodities that are vital for emerging and low-carbon technologies. Examples of such commodities include cobalt and graphite for rechargeable batteries, tellurium in thin-film solar photovoltaics and rare earth elements (REE) in permanent magnets,
Authors
Karen D. Kelley, David Huston, Jan Peter
Tectonic and magmatic controls on the metallogenesis of porphyry deposits in Alaska
Porphyry Cu and Mo deposits and occurrences are found throughout Alaska; they formed episodically during repeated subduction and arc-continent collisions spanning the Silurian to Quaternary. Porphyry systems occur in continental-margin and island arcs, which are broadly grouped into pre-accretionary or post-accretionary arcs. Pre-Mesozoic occurrences formed in continental or island arcs prior to a
Authors
Douglas C. Kreiner, James V. Jones, Karen D. Kelley, Garth E. Graham
Alkalic-type epithermal gold deposit model
This report summarizes the primary characteristics of alkalic-type epithermal gold (Au) deposits and provides an updated descriptive model. These deposits, primarily of Mesozoic to Neogene age, are among the largest epithermal gold deposits in the world. Considered a subset of low-sulfidation epithermal deposits, they are spatially and genetically linked to small stocks or clusters of intrusions c
Authors
Karen D. Kelley, Paul G. Spry, Virginia T. McLemore, David L. Fey, Eric D. Anderson
Hydrogeochemistry in the Yukon-Tanana Upland region of east-central Alaska: Possible exploration tool for porphyry-style deposits
A hydrogeochemical study using high resolution ICP-MS was undertaken at the Taurus and other porphyry Cu-Mo(-Au) occurrences and Ag-Au-Cu (+/- Pb, Zn) occurrences with epithermal-style characteristics in the Yukon-Tanana upland region of eastern Alaska. Surface water samples were collected from 30 sites on creeks that drain known deposits and occurrences and surrounding presumably unmineralized ar
Authors
Karen D. Kelley, Garth E. Graham
International geoscience collaboration to support critical mineral discovery
The importance of critical minerals and the need to expand and diversify critical mineral supply chains has been endorsed by the Federal governments of Australia, Canada, and the United States. The geoscience organizations of Geoscience Australia, the Geological Survey of Canada and the U.S. Geological Survey have created the Critical Minerals Mapping Initiative to build a diversified critical min
Authors
, ,
Evaluation of the analytical methods used to determine the elemental concentrations found in the stream geochemical dataset compiled for Alaska
A recent U.S. Geological Survey data compilation of stream-sediment geochemistry for Alaska contains decades of analyses collected under numerous Federal and State programs. The compiled data were determined by various analytical methods. Some samples were reanalyzed by a different analytical method than the original, resulting in some elements having concentrations reported by multiple analytical
Authors
Bronwen Wang, Karl J. Ellefsen, Matthew Granitto, Karen D. Kelley, Susan M. Karl, George N. D. Case, Douglas C. Kreiner, Courtney L. Amundson