Skip to main content
U.S. flag

An official website of the United States government

Andrew G Hunt

Andy Hunt is a Research Geologist with the Geology, Geophysics, and Geochemistry Science Center.

Science and Products

Ivotuk Hills

Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

The Project objective is to facilitate the full potential of stable isotope (C,H,N,O,S), noble gas isotope (He, Ar, Ne, Ar, Kr, Xe), active gas geochemistry (CO2, H2S, SO2, CH4, HF, HCl, N2, H2, organics, light hydrocarbons), and solute geochemistry measurements of minerals and fluids (including single fluid inclusions) in multidisciplinary studies of fundamental processes that affect mineral...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

The Project objective is to facilitate the full potential of stable isotope (C,H,N,O,S), noble gas isotope (He, Ar, Ne, Ar, Kr, Xe), active gas geochemistry (CO2, H2S, SO2, CH4, HF, HCl, N2, H2, organics, light hydrocarbons), and solute geochemistry measurements of minerals and fluids (including single fluid inclusions) in multidisciplinary studies of fundamental processes that affect mineral...
Learn More

Geochemical and hydrologic data supporting assessment of a low-temperature geothermal system in Steamboat Springs, Colorado Geochemical and hydrologic data supporting assessment of a low-temperature geothermal system in Steamboat Springs, Colorado

Geothermal springs may be connected to both shallow and deep groundwater sources, and identification of variable spring sources may assist with resource management of geothermal systems. Numerous geothermal springs exist near the Yampa River in Steamboat Springs, Colorado and local water and land management agencies could benefit from information on the sources of these springs. This...
By
Colorado Water Science Center

Chemical and isotopic compositions of gases from volcanic and geothermal areas in California Chemical and isotopic compositions of gases from volcanic and geothermal areas in California

Gas chemical and isotopic compositions are reported for samples collected from 9 volcanic and geothermal areas in California: Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Mono Lake Volcanic Field, Long Valley Caldera, Mammoth Mountain, Coso Volcanic Field, and Salton Sea Geothermal Field. Beginning in 2014, gas samples were collected as part of...
By
Volcano Science Center

Noble Gas Isotopic Data from Fluid Inclusions Contained in the Te-bearing Adularia-Sericite Epithermal Au-Ag Deposits in a Calc-Alkaline Magmatic Arc, NE China Noble Gas Isotopic Data from Fluid Inclusions Contained in the Te-bearing Adularia-Sericite Epithermal Au-Ag Deposits in a Calc-Alkaline Magmatic Arc, NE China

The contents of this data release represent the results of the noble gas composition analysis and are presented in support of the planned publication Gao et al., 2023, titled Lead and noble gas isotopic constraints on the origin of Te-bearing adularia-sericite epithermal Au-Ag deposits in a calc-alkaline magmatic arc. Tellurium (Te)-bearing adularia-sericite epithermal Au-Ag deposits are...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Hydrochemistry and Age Date Tracers from Springs, Streams, and Rivers in the Arctic National Wildlife Refuge, 2019-2022 Hydrochemistry and Age Date Tracers from Springs, Streams, and Rivers in the Arctic National Wildlife Refuge, 2019-2022

These data include water chemistry from springs, streams, rivers, and shallow groundwater collected in the Arctic National Wildlife Refuge in northern Alaska. Chemical analyses were performed for hydrochemical parameters including field parameters, major ions, nutrients, metals, stable isotopes of water, and tritium, as well as for dissolved gases useful for determining the timescale...
By
Alaska Science Center

Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district

This dataset is a collection of geochemical data on samples from the Stibnite-Yellow Pine district of Idaho. The datasets include: whole rock geochemistry; lead, strontium and neodymium isotope chemistry of sulfides and whole rock samples by isotope dilution-thermal-mass spectrometry (ID-TIMS); in situ sulfur isotope chemistry of sulfides by laser ablation-multi collector-inductively...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025) Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025)

There are over 10,000 hydrothermal features in Yellowstone National Park (YNP), where waters have pH values ranging from about 1 to 10 and surface temperatures up to 95 °C. Active hydrothermal areas in YNP provide insight into a variety of processes occurring at depth, such as water-rock and oxidation-reduction (redox) reactions, the formation of alteration minerals, and microbial...
By
Water Resources Mission Area, Volcano Hazards Program, Yellowstone
Filter Total Items: 66

Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA

Alluvial valley aquifers are important sources of water supply in many areas but effects of co-located oil and gas development on these resources have not been widely reported, especially in settings where recharge is dominated by stream infiltration. Interpreting the presence of geochemical indicators in the context of hydrology, geology, and other factors provides a more complete...
Authors
Jennifer S. Stanton, Michael J. Stephens, Matthew K. Landon, David H. Shimabukuro, Andrew G. Hunt, Justin T. Kulongoski, Isabelle M. Cozzarelli, Theron A. Sowers
By
California Water Science Center

Gas chemistry and isotope data for volcano monitoring at the Lassen Volcanic Center, Lassen Volcanic National Park Gas chemistry and isotope data for volcano monitoring at the Lassen Volcanic Center, Lassen Volcanic National Park

This report presents chemical and isotopic compositions of volcanic gases collected from thermal areas within Lassen Volcanic National Park in northern California from 1974 through 2019. As the southernmost volcano in the Cascade Range and designated a very-high-threat volcano by the U.S. Geological Survey, the Lassen Volcanic Center (LVC) requires consistent monitoring to assess...
Authors
Deborah Bergfeld, Jennifer L. Lewicki, Sara Peek, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

Gas emissions from the Sulphur Bank Mercury Mine hydrothermal system, Clear Lake volcanic field, California Gas emissions from the Sulphur Bank Mercury Mine hydrothermal system, Clear Lake volcanic field, California

The Sulphur Bank Mercury Mine (SBMM) hydrothermal system offers insights into active degassing processes in the Clear Lake volcanic field (CLVF), a high-threat region based on its record of Holocene eruptions and proximity to populated areas. Here we present chemical and isotopic analyses of gas samples collected between 2015 and 2023, along with the first comprehensive CO2 flux survey...
Authors
Jennifer L. Lewicki, Sara Peek, Laura E. Clor, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA

To improve our understanding of hydrothermal activity on the Yellowstone Plateau volcanic field, we collected and analyzed a large data set of δ2H, δ18O, and the 3H concentrations of circum-neutral and alkaline waters. We find that (a) hot springs are fed by recharge throughout the volcanic plateau, likely focused through fractured, permeable tuff units. Previous work had stressed the...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Bryant Jurgens, Jacob B. Lowenstern, Laura E. Clor, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

Controls on water quality below a reclaimed surface coal mine, southeastern Montana Controls on water quality below a reclaimed surface coal mine, southeastern Montana

Coal mining and reclamation can have a profound influence on hydrogeologic systems, with clear consequences for groundwater quality, yet their long-term influence on downgradient water quality over time following reclamation is less well documented. Geochemical trends were evaluated in water quality downgradient of a fully reclaimed landscape at the former Big Sky Mine in the Rosebud...
Authors
Skye Keeshin, Stephanie A. Ewing, Elizabeth B Meredith, Robert A. Payne, W. Payton Gardner, Andrew G. Hunt
By
Geology, Geophysics, and Geochemistry Science Center

Groundwater quality near the Placerita Oil Field, California, 2018 Groundwater quality near the Placerita Oil Field, California, 2018

Groundwater-quality data and potential fluid-migration pathways near the Placerita Oil Field in Los Angeles County, California, were examined by the U.S. Geological Survey to determine if oil-field fluids (water and gas from oil-producing and non-producing zones) have mixed with groundwater resources. Six of the 13 new groundwater samples collected for this study contained petroleum...
Authors
Jennifer S. Stanton, Matthew K. Landon, David H. Shimabukuro, Justin T. Kulongoski, Andrew G. Hunt, Peter B. McMahon, Isabelle M. Cozzarelli, Robert Anders, Theron A. Sowers
By
Water Resources Mission Area, California Water Science Center, New England Water Science Center

Science and Products

Ivotuk Hills

Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

The Project objective is to facilitate the full potential of stable isotope (C,H,N,O,S), noble gas isotope (He, Ar, Ne, Ar, Kr, Xe), active gas geochemistry (CO2, H2S, SO2, CH4, HF, HCl, N2, H2, organics, light hydrocarbons), and solute geochemistry measurements of minerals and fluids (including single fluid inclusions) in multidisciplinary studies of fundamental processes that affect mineral...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

Isotope and Chemical Methods for Mineral and Geoenvironmental Assessments and Support of USGS Science Strategy

The Project objective is to facilitate the full potential of stable isotope (C,H,N,O,S), noble gas isotope (He, Ar, Ne, Ar, Kr, Xe), active gas geochemistry (CO2, H2S, SO2, CH4, HF, HCl, N2, H2, organics, light hydrocarbons), and solute geochemistry measurements of minerals and fluids (including single fluid inclusions) in multidisciplinary studies of fundamental processes that affect mineral...
Learn More

Geochemical and hydrologic data supporting assessment of a low-temperature geothermal system in Steamboat Springs, Colorado Geochemical and hydrologic data supporting assessment of a low-temperature geothermal system in Steamboat Springs, Colorado

Geothermal springs may be connected to both shallow and deep groundwater sources, and identification of variable spring sources may assist with resource management of geothermal systems. Numerous geothermal springs exist near the Yampa River in Steamboat Springs, Colorado and local water and land management agencies could benefit from information on the sources of these springs. This...
By
Colorado Water Science Center

Chemical and isotopic compositions of gases from volcanic and geothermal areas in California Chemical and isotopic compositions of gases from volcanic and geothermal areas in California

Gas chemical and isotopic compositions are reported for samples collected from 9 volcanic and geothermal areas in California: Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, Mono Lake Volcanic Field, Long Valley Caldera, Mammoth Mountain, Coso Volcanic Field, and Salton Sea Geothermal Field. Beginning in 2014, gas samples were collected as part of...
By
Volcano Science Center

Noble Gas Isotopic Data from Fluid Inclusions Contained in the Te-bearing Adularia-Sericite Epithermal Au-Ag Deposits in a Calc-Alkaline Magmatic Arc, NE China Noble Gas Isotopic Data from Fluid Inclusions Contained in the Te-bearing Adularia-Sericite Epithermal Au-Ag Deposits in a Calc-Alkaline Magmatic Arc, NE China

The contents of this data release represent the results of the noble gas composition analysis and are presented in support of the planned publication Gao et al., 2023, titled Lead and noble gas isotopic constraints on the origin of Te-bearing adularia-sericite epithermal Au-Ag deposits in a calc-alkaline magmatic arc. Tellurium (Te)-bearing adularia-sericite epithermal Au-Ag deposits are...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Hydrochemistry and Age Date Tracers from Springs, Streams, and Rivers in the Arctic National Wildlife Refuge, 2019-2022 Hydrochemistry and Age Date Tracers from Springs, Streams, and Rivers in the Arctic National Wildlife Refuge, 2019-2022

These data include water chemistry from springs, streams, rivers, and shallow groundwater collected in the Arctic National Wildlife Refuge in northern Alaska. Chemical analyses were performed for hydrochemical parameters including field parameters, major ions, nutrients, metals, stable isotopes of water, and tritium, as well as for dissolved gases useful for determining the timescale...
By
Alaska Science Center

Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district Trace element chemistry of sulfides and quartz, in situ sulfur isotope values of sulfides, cathodoluminescence of quartz, fluid inclusion microthermometry and raman, and radiogenic isotope and whole rock geochemistry from the Stibnite-Yellow Pine district

This dataset is a collection of geochemical data on samples from the Stibnite-Yellow Pine district of Idaho. The datasets include: whole rock geochemistry; lead, strontium and neodymium isotope chemistry of sulfides and whole rock samples by isotope dilution-thermal-mass spectrometry (ID-TIMS); in situ sulfur isotope chemistry of sulfides by laser ablation-multi collector-inductively...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025) Water-Chemistry and Isotope Data for Selected Springs, Geysers, Streams, and Rivers in Yellowstone National Park, Wyoming (ver. 2.0, March 2025)

There are over 10,000 hydrothermal features in Yellowstone National Park (YNP), where waters have pH values ranging from about 1 to 10 and surface temperatures up to 95 °C. Active hydrothermal areas in YNP provide insight into a variety of processes occurring at depth, such as water-rock and oxidation-reduction (redox) reactions, the formation of alteration minerals, and microbial...
By
Water Resources Mission Area, Volcano Hazards Program, Yellowstone
Filter Total Items: 66

Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA Groundwater quality near an oil field in a stream-dominated recharge setting, California, USA

Alluvial valley aquifers are important sources of water supply in many areas but effects of co-located oil and gas development on these resources have not been widely reported, especially in settings where recharge is dominated by stream infiltration. Interpreting the presence of geochemical indicators in the context of hydrology, geology, and other factors provides a more complete...
Authors
Jennifer S. Stanton, Michael J. Stephens, Matthew K. Landon, David H. Shimabukuro, Andrew G. Hunt, Justin T. Kulongoski, Isabelle M. Cozzarelli, Theron A. Sowers
By
California Water Science Center

Gas chemistry and isotope data for volcano monitoring at the Lassen Volcanic Center, Lassen Volcanic National Park Gas chemistry and isotope data for volcano monitoring at the Lassen Volcanic Center, Lassen Volcanic National Park

This report presents chemical and isotopic compositions of volcanic gases collected from thermal areas within Lassen Volcanic National Park in northern California from 1974 through 2019. As the southernmost volcano in the Cascade Range and designated a very-high-threat volcano by the U.S. Geological Survey, the Lassen Volcanic Center (LVC) requires consistent monitoring to assess...
Authors
Deborah Bergfeld, Jennifer L. Lewicki, Sara Peek, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

Gas emissions from the Sulphur Bank Mercury Mine hydrothermal system, Clear Lake volcanic field, California Gas emissions from the Sulphur Bank Mercury Mine hydrothermal system, Clear Lake volcanic field, California

The Sulphur Bank Mercury Mine (SBMM) hydrothermal system offers insights into active degassing processes in the Clear Lake volcanic field (CLVF), a high-threat region based on its record of Holocene eruptions and proximity to populated areas. Here we present chemical and isotopic analyses of gas samples collected between 2015 and 2023, along with the first comprehensive CO2 flux survey...
Authors
Jennifer L. Lewicki, Sara Peek, Laura E. Clor, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA The systematics of stable hydrogen (δ2H) and oxygen (δ18O) isotopes and tritium (3H) in the hydrothermal system of the Yellowstone Plateau volcanic field, USA

To improve our understanding of hydrothermal activity on the Yellowstone Plateau volcanic field, we collected and analyzed a large data set of δ2H, δ18O, and the 3H concentrations of circum-neutral and alkaline waters. We find that (a) hot springs are fed by recharge throughout the volcanic plateau, likely focused through fractured, permeable tuff units. Previous work had stressed the...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Bryant Jurgens, Jacob B. Lowenstern, Laura E. Clor, Andrew G. Hunt
By
Volcano Hazards Program, Volcano Science Center

Controls on water quality below a reclaimed surface coal mine, southeastern Montana Controls on water quality below a reclaimed surface coal mine, southeastern Montana

Coal mining and reclamation can have a profound influence on hydrogeologic systems, with clear consequences for groundwater quality, yet their long-term influence on downgradient water quality over time following reclamation is less well documented. Geochemical trends were evaluated in water quality downgradient of a fully reclaimed landscape at the former Big Sky Mine in the Rosebud...
Authors
Skye Keeshin, Stephanie A. Ewing, Elizabeth B Meredith, Robert A. Payne, W. Payton Gardner, Andrew G. Hunt
By
Geology, Geophysics, and Geochemistry Science Center

Groundwater quality near the Placerita Oil Field, California, 2018 Groundwater quality near the Placerita Oil Field, California, 2018

Groundwater-quality data and potential fluid-migration pathways near the Placerita Oil Field in Los Angeles County, California, were examined by the U.S. Geological Survey to determine if oil-field fluids (water and gas from oil-producing and non-producing zones) have mixed with groundwater resources. Six of the 13 new groundwater samples collected for this study contained petroleum...
Authors
Jennifer S. Stanton, Matthew K. Landon, David H. Shimabukuro, Justin T. Kulongoski, Andrew G. Hunt, Peter B. McMahon, Isabelle M. Cozzarelli, Robert Anders, Theron A. Sowers
By
Water Resources Mission Area, California Water Science Center, New England Water Science Center
Was this page helpful?