James Paces
Primary research responsibilities includes collection of radiogenic isotope data (U-series and Sr) used to date Quaternary deposits and provide natural tracers of mass flow through near-surface environments.
EMPLOYMENT HISTORY
Scientist Emeritus, USGS, Geology and Environmental Change Science Center, (2021-)
Research Geologist, USGS, Geology and Environmental Change Science Center, (2010 - 2020)
Geochronological and radiogenic isotope studies associated with 1) Quaternary landscape evolution for Geologic-Mapping Studies at Buffalo National River, AR; Greater Platte River basin, CO; Rio Grande Rift, NM & CO, 2) probabilistic seismic hazard analyses, eastern WA, 3) Pleistocene water-table fluctuations and aquifer sources at Wind Cave NP, SD, 4) ages of megafauna and archaeological sites, CO & CA, 5) hydrologic sources and mixing in modern and paleohydrologic environments (Pahranagat NWR, NV; Sacramento-San Joaquin Delta, CA; Yellowstone NP, WY; Gallatin Valley, MT; upper Santa Cruz River basin; AZ), 6) structural evolution of Channel Islands NP, CA, 7) timing of U mineralization, TX & VA.
Research Hydrologist, USGS, Yucca Mountain Project Branch, (1992 - 2010)
Geochemical and isotopic characterization of the Nation’s proposed high-level radioactive waste repository at Yucca Mountain, NV. Studies of both surface- and subsurface-based geochronology, hydrology, and paleoclimate investigations using Sr and U-Th isotopes to characterize modern and Pleistocene hydrologic processes.
Geologist, Natl. Res. Council Post-doc, USGS, Branch of Isotope Geology (1990 - 1991)
1) Isotopic (U-Pb, Rb-Sr, Sm-Nd) investigation of lower crustal nodules from Jurassic kimberlites, MI, 2) High-precision, single-zircon U-Pb dating of 1.1 Ga mafic intrusions in the Duluth Complex, MN.
Geologist, Post-doc fellow, Univ. Tennessee (1989)
Sr- and Nd-isotope study of whole rocks and mineral separates of Apollo 17 mare basalts.
EDUCATION
Ph.D. in Geology, Michigan Technological University, Houghton, Michigan, 1988; Magmatic processes, evolution and mantle source characteristics contributing to the petrogenesis of Midcontinent Rift Basalts: Portage Lake Volcanics, Keweenaw Peninsula, MI
B.S. in Geology (with honors), University of Oregon, Eugene, Oregon, 1978
AWARDS
USGS Superior Service Award, 2005
GSA Fellow
Colorado Scientific Society President, 2020
PROFESSIONAL AFFILIATIONS
Geological Society of America
American Geophysical Union
Geochemical Society
International Association of Geochemistry
Science and Products
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...
Filter Total Items: 20
Isotopic, geochronologic and soil temperature data for Holocene and late Pleistocene soil carbonates of the San Luis Valley, Colorado and New Mexico, USA
This data release contains radiocarbon dates and clumped isotope ratios for soil carbonates as well as observed soil temperatures for study sites in the San Luis Valley, Colorado and New Mexico, USA. The companion publication can be found at https://doi.org/10.1029/2023GC011221.
Mineralogy, chemistry and isotope composition of silica sinter deposits from the Upper Geyser Basin, Yellowstone National Park (ver. 2.0, April 2021)
Summary: Siliceous sinter samples were collected from multiple geysers in the Upper Geyser Basin of Yellowstone National Park in 2018. These silica sinter samples were collected and analyzed as a part of a multi-year research investigation into the age and geochemistry of hydrothermal features in the Upper Geyser Basin. Samples were collected along the stratigraphy of each feature. From...
Isotope analyses (234U/238U, 87Sr/86Sr, δ13C, and δ18O) and U-series disequilibrium ages for speleothem, water, and rock samples associated with Fitton Cave, Buffalo National River, Arkansas, USA
This data release contains tabular data (comma-separated-value files) of natural radiogenic isotopes of strontium, uranium, and thorium for samples of modern water, speleothems, associated with Fitton Cave, north central Arkansas, as well as rock that host the cave deposits. In addition, U-series ages (230Th/U dates and model 234U/238U dates) are calculated from those data for subsamples...
Mineralogy, strontium (87Sr/86Sr), oxygen (18O/16O) and carbon (13C/12C) isotope composition, elemental concentrations, and U-Th disequilibrium ages for travertine deposits from various locations in Yellowstone National Park, USA
Chemical changes in hot springs, as recorded by thermal waters and their mineral deposits, provide a window into the evolution of Yellowstone’s postglacial hydrothermal system. Travertine precipitated from thermal waters provide a record of chemical changes through time because they can be dated using U-series disequilibrium geochronology. These temporal data, along with measured...
Elemental and Strontium Isotopic Composition of Select Central Plateau and Upper Basin Member Rhyolites, Yellowstone Plateau Volcanic Field
The Yellowstone Plateau Volcanic field consists of lavas from the last two million years. The most recent volcanic units are the Central Plateau Member and the older Upper Basin Member rhyolites (Christiansen, 2001). Investigations into the elemental and isotopic composition of these lavas can provide insight into the recent volcanic history of the different eruptive episodes and provide...
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...
Sr and U concentrations and radiogenic isotope compositions (87Sr/86Sr, 234U/238U) of thermal waters, streamflow, travertine, and rock samples along with U-Th disequilibrium ages for travertine deposits from various locations in Yellowstone National Park,
This data provides locations and technical specifications of legacy and current versions of the United States Wind Turbines database. Almost all of which are utility-scale. Utility-scale turbines are ones that generate power and feed it into the grid, supplying a utility with energy. They are usually much larger than turbines that would feed a homeowner or business. Each release...
Strontium and uranium isotopic compositions (87Sr/86Sr and 234U/238U) of mid- to late-Holocene lacustrine sediments from Lower Pahranagat Lake, Pahranagat National Wildlife Refuge, Lincoln County, Nevada
This data release includes a table of concentrations (Sr, U) and radiogenic-isotope compositions (87Sr/86Sr, 234U/238U) for samples of modern lake water as well as a table of isotopic compositions (87Sr/86Sr and 234U/238U) for carbonate-rich samples from a 12.4-m-long composite core of lacustrine sediment from Lower Pahranagat Lake in southeastern Nevada, USA. Stratigraphic and...
Sr concentrations and 87Sr/86Sr data used to determine the Sr-chronostratigraphic age of sirenian fossils on Santa Rosa Island, Channel Islands National Park, California, USA
This data release includes a table of Sr concentrations and 87Sr/86Sr data used to evaluate primary seawater isotope compositions of marine invertebrate shell material used to estimate the Sr-chronostratigraphic age of sediments hosting early Miocene sirenian fossils on Santa Rosa Island of the Channel Island National Park, Ventura County, California
Database for the geologic map of the upper Santa Cruz River basin, southern Arizona
This digital publication contains the database, base maps, and style files used to build the geologic map of the upper Santa Cruz River basin in southern Arizona published in U.S. Geological Survey Scientific Investigations Map 3490 (Page and others, 2023). Shapefiles are also included for the user’s convenience. In the database, there are polygon features outlining the map units and...
Sr-, U-, H- and O-isotope data used to evaluate water sources in the Potrero Creek Wetlands, Upper Santa Cruz Basin, southern Arizona, USA
This data release includes a table of 87Sr/86Sr, 234U/238U, δ2H, and δ18O isotope data used to evaluate groundwater- and surface-water-sources contributing to water in perennial wetlands near the mouth of Potrero Creek within the Upper Santa Cruz Basin near Nogales, AZ. Interpretations of those data are discussed in the pamphlet accompanying the USGS Scientific Investigations Map SIM...
Uranium- and thorium-isotope data used to estimate uranium-series ages of Pleistocene lake deposits in the Lake Manix basin, Mojave Desert, California
This data release contains numerical U- and Th-isotopic data used to calculate uranium-series age estimates and initial 234U/238U activity ratios for samples of carbonate-rich clast coatings, oncoidal tufa rinds, calcite-replaced rhizoliths, carbonate nodules, and ostracod shells from sites associated with different lake levels of paleo Lake Manix near Barsow, CA. In addition, measured U...
Geologic map and hydrogeologic investigations of the upper Santa Cruz River basin, southern Arizona
This report includes an updated geologic map and cross sections of the upper Santa Cruz River basin, southern Arizona. The map and cross sections describe the geometry, thickness, and structure of the Miocene to Holocene units which form the main aquifers in the basin. The report also includes results of new hydrogeologic studies including (1) mapping and defining depth to bedrock based...
Geologic map of the Fort Morgan 7.5' quadrangle, Morgan County, Colorado
The Fort Morgan 7.5′ quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the late Pliocene to the...
Geologic map of the Weldona 7.5' quadrangle, Morgan County, Colorado
The Weldona 7.5′ quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the Pleistocene to the present...
Geologic map of the Masters 7.5' quadrangle, Weld and Morgan Counties, Colorado
The Masters 7.5' quadrangle is located along the South Platte River corridor on the semiarid plains of eastern Colorado and contains surficial deposits that record alluvial, eolian, and hillslope processes that have operated in concert with environmental changes from Pleistocene to present time. The South Platte River, originating high in the Colorado Front Range, has played a major role...
Geologic and geophysical maps of the Las Vegas 30' x 60' quadrangle, Clark and Nye counties, Nevada, and Inyo County, California
Las Vegas and Pahrump are two of the fastest growing cities in the US, and the shortage of water looms as among the greatest future problems for these cities. These new maps of the Las Vegas 30 x 60-minute quadrangle provide a geologic and geophysical framework and fundamental earth science database needed to address societal issues such as ground water supply and contamination, surface...
Geologic map of the Mound Spring quadrangle, Nye and Clark Counties, Nevada, and Inyo County, California
The Mound Spring quadrangle, the southwestern-most 7.5' quadrangle of the area of the Las Vegas 1:100,000-scale quadrangle, is entirely within the Pahrump Valley, spanning the Nevada/California State line. New geologic mapping of the predominantly Quaternary materials is combined with new studies of gravity and geochronology in this quadrangle. Eleven predominantly fine-grained units are...
Filter Total Items: 87
Radiogenic strontium- and uranium-isotope tracers of water-rock interactions and hydrothermal flow in the Upper Geyser Basin, Yellowstone Plateau Volcanic Field, USA
Natural radiogenic isotopes (primarily 87Sr/86Sr) from hot springs in the Upper Geyser Basin of the Yellowstone Plateau volcanic field and associated rocks were used to evaluate groundwater flow patterns, water-rock reactions, and the extent of mixing between various groundwater sources. Thermal waters have very low uranium concentrations and 234U/238U activity ratios near 1.0, which...
Authors
James B. Paces, Shaul Hurwitz, Lauren N Harrison, Jacob B. Lowenstern, R. Blaine McCleskey
Clumped isotopes record a glacial-interglacial shift in seasonality of soil carbonate accumulation in the San Luis Valley, southern Rocky Mountains, USA
Clumped isotope paleothermometry using pedogenic carbonates is a powerful tool for investigating past climate changes. However, location-specific seasonal patterns of precipitation and soil moisture cause systematic biases in the temperatures they record, hampering comparison of data across large areas or differing climate states. To account for biases, more systematic studies of...
Authors
Adam M. Hudson, Julia R. Kelson, James B. Paces, Chester A. Ruleman, Katharine W. Huntington, Andrew J. Schauer
Travertine records climate-induced transformations of the Yellowstone hydrothermal system from the late Pleistocene to the present
Chemical changes in hot springs, as recorded by thermal waters and their deposits, provide a window into the evolution of the postglacial hydrothermal system of the Yellowstone Plateau Volcanic Field. Today, most hydrothermal travertine forms to the north and south of the ca. 631 ka Yellowstone caldera where groundwater flow through subsurface sedimentary rocks leads to calcite...
Authors
Lauren N Harrison, Shaul Hurwitz, James B. Paces, Cathy Whitlock, Sara E. Peek, Joseph M. Licciardi
Evaluation of hydrologic processes in the eastern Snake River Plain aquifer using uranium and strontium isotopes, Idaho National Laboratory, eastern Idaho
Waste constituents discharged to the eastern Snake River Plain aquifer at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) pose risks to the water quality of the aquifer. To understand these risks, the U.S. Geological Survey, in cooperation with the DOE, is conducting geochemical studies to better understand the hydrologic processes at the INL that affect the movement...
Authors
Gordon W. Rattray, James B. Paces
Strontium isotope chronostratigraphic age of a sirenian fossil site on Santa Rosa Island, Channel Islands National Park, California
Fossils in the order Sirenia (family Dugongidae) from Santa Rosa Island, part of Channel Islands National Park in southern California, provide rare temporal and spatial links between earlier and later evolutionary forms of dugongids, and add information about their dispersal into the northeastern Pacific region. Marine sedimentary rocks containing these fossils have characteristics of...
Authors
James B. Paces, Scott A. Minor, Kevin Schmidt, Jonathan N. Hoffman
Climate-driven mid- to late Holocene hydrologic evolution of arid wetlands documented by strontium, uranium, and oxygen isotopes from Lower Pahranagat Lake, southern Nevada, USA
Lacustrine carbonates in a 12.4-m-long core from Lower Pahranagat Lake (LPAH), southern Nevada, indicate that radiogenic isotopes of Sr and U (87Sr/86Sr and 234U/238U) preserve evidence of past variations in water sources and evolving hydrologic conditions. Sr and U isotope compositions in LPAH carbonates fall within the range defined by the three primary groundwater sources in...
Authors
Kevin M. Theissen, James B. Paces
The Coles Hill uranium deposit, Virginia, USA: Geology, geochemistry, geochronology, and genetic model
The Coles Hill uranium deposit with an indicated resource of about 130 million lbs. of U3O8 is the largest unmined uranium deposit in the United States. The deposit is hosted in the Taconian (approximately 480 – 450 Ma) Martinsville igneous complex, which consists of the Ordovician Leatherwood Granite (granodiorite) and Silurian Rich Acres Formation (diorite). The host rock was...
Authors
Susan M. Hall, J.S. Beard, Christopher J. Potter, R.J. Bodnar, Leonid A. Neymark, James B. Paces, Craig A. Johnson, G.N. Breit, Robert A. Zielinski, G. J. Aylor
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
The US Environmental Protection Agency's short-term freshwater effluent test methods include a fish (Pimephales promelas), a cladoceran (Ceriodaphnia dubia), and a green alga (Raphidocelis subcapitata). There is a recognized need for additional taxa to accompany the three standard species for effluent testing. An appropriate additional taxon is unionid mussels because mussels are widely...
Authors
Marith C. Reheis, David Miller, James B. Paces, Charles Gifford Oviatt, Joanna R. Redwine, Darrell S. Kaufman, Jordon E. Bright, Elmira Wan
Dating silica sinter (geyserite): A cautionary tale
We describe a new effort to date hydrothermal silica sinter deposits (geyserite) from the Upper Geyser Basin of Yellowstone National Park using 14C of co-deposited organic matter, U-series and cosmogenic 10Be methods. A majority of the samples were collected from stratigraphic sections, mainly at Riverside, Giant, and Castle Geysers. Ages obtained from 41 14C analyses range from modern...
Authors
Dakota Churchill, Michael Manga, Shaul Hurwitz, Sara E. Peek, Joseph M. Licciardi, James B. Paces
Hydrothermal activity in the southwest Yellowstone Plateau Volcanic Field
In the past two decades, the U.S. Geological Survey and the National Park Service have studied hydrothermal activity across the Yellowstone Plateau Volcanic Field (YPVF) to improve the understanding of the magmatic-hydrothermal system and to provide a baseline for detecting future anomalous activity. In 2017 and 2018 we sampled water and gas over a large area in the southwest YPVF and...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Deborah Bergfeld, Sara E. Peek, David Susong, David A. Roth, Jefferson Hungerford, Erin B White, Lauren N Harrison, Behnaz Hosseini, R. Greg Vaughan, Andrew G. Hunt, James B. Paces
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
The Tecopa basin in eastern California was a terminal basin that episodically held lakes during most of the Quaternary until the basin and its modern stream, the Amargosa River, became tributary to Death Valley. Although long studied for its sedimentology, diagenesis, and paleomagnetism, the basin’s lacustrine and paleoclimate history has not been well understood, and conflicting...
Authors
Marith C. Reheis, John Caskey, Jordon E. Bright, James B. Paces, Shannon A. Mahan, Elmira Wan
300,000 yr history of water-table fluctuations at Wind Cave, South Dakota, USA—Scale, timing, and groundwater mixing in the Madison Aquifer
Deposits of calcite coating the lower passages of Wind Cave in the southern Black Hills of South Dakota were precipitated under phreatic conditions. Data from samples associated with a new cave survey and hydrologic studies indicate that past water tables within Wind Cave reached a maximum height of 45 m above modern levels but were mostly confined to 25 m or less. Uranium-series ages...
Authors
James B. Paces, Margaret V. Palmer, Arthur N. Palmer, Andrew J. Long, Matthew P. Emmons
Non-USGS Publications**
Paces, J.B., Nakai, S., Neal, C.R., Taylor, L.A., Halliday, A.N., and Lee, D-C, 1991, A Sr and Nd isotopic study of Apollo 17 high-Ti basalts: resolution of ages, evolution of magmas, and origins of source heterogeneities: Geochimica et Cosmochimica Acta, v. 55, p. 2025-2043.
Neal, C.R., Taylor, L.A., Davidson, J.P., Holden, P., Halliday, A.N., Paces, J.B., Clayton, R.N., and Mayeda, T.K., 1990, Eclogites with oceanic crustal and mantle signatures from the Bellsbank Kimberlite, South Africa, Part II: Radiogenic isotopes and geochemical evolution: Earth and Planetary Science Letters, v. 99, p. 362-379.
Davis, D.W., and Paces, J.B., 1990, Time resolution of geological events on the Keweenaw Peninsula and implications for development of the Midcontinent Rift system: Earth and Planetary Science Letters, v. 97, p. 54-64.
Paces, J.B., and Bell, K., 1989, Non-depleted sub-continental mantle beneath the Superior Province of the Canadian Shield: Nd-Sr isotopic and trace element evidence from Midcontinent Rift basalts: Geochimica et Cosmochimica Acta, v. 53, p. 2023-2035.
Zolensky, M.E., Sylvester, P.J., and Paces, J.B., 1988, Origin and significance of blue coloration in quartz from Llano Rhyolite (Llanite), north-central Llano County, Texas: American Mineralogist, v. 73, p. 313-323.
Bornhorst, T.J., Kalliokoski, J., and Paces, J.B., 1986, The Keweenaw Native-Copper District, in Brown, A.C., Kirkham, R.V. (eds.), Proterozoic Sediment-hosted Stratiform Copper Deposits of Upper Michigan and Belt Supergroup of Idaho and Montana: Geological Association of Canada/Mineralogical Association of Canada/Canadian Geophysical Union Joint Annual Meeting, Ottawa '86, Field Trip 1 Guidebook, p. 21-36.
McDowell, S.D., and Paces, J.B., 1985, Carbonate alteration minerals in the Salton Sea geothermal system, California, USA: Mineral Magazine, v. 49, p. 469-479.
Wilson, M.L., Paces, J.B., and Ruotsala, A.P., 1984, Fluorapatite from the King Lithia mine, Custer County, South Dakota: Mineral Record v. 15, p. 361-366.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
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...
Filter Total Items: 20
Isotopic, geochronologic and soil temperature data for Holocene and late Pleistocene soil carbonates of the San Luis Valley, Colorado and New Mexico, USA
This data release contains radiocarbon dates and clumped isotope ratios for soil carbonates as well as observed soil temperatures for study sites in the San Luis Valley, Colorado and New Mexico, USA. The companion publication can be found at https://doi.org/10.1029/2023GC011221.
Mineralogy, chemistry and isotope composition of silica sinter deposits from the Upper Geyser Basin, Yellowstone National Park (ver. 2.0, April 2021)
Summary: Siliceous sinter samples were collected from multiple geysers in the Upper Geyser Basin of Yellowstone National Park in 2018. These silica sinter samples were collected and analyzed as a part of a multi-year research investigation into the age and geochemistry of hydrothermal features in the Upper Geyser Basin. Samples were collected along the stratigraphy of each feature. From...
Isotope analyses (234U/238U, 87Sr/86Sr, δ13C, and δ18O) and U-series disequilibrium ages for speleothem, water, and rock samples associated with Fitton Cave, Buffalo National River, Arkansas, USA
This data release contains tabular data (comma-separated-value files) of natural radiogenic isotopes of strontium, uranium, and thorium for samples of modern water, speleothems, associated with Fitton Cave, north central Arkansas, as well as rock that host the cave deposits. In addition, U-series ages (230Th/U dates and model 234U/238U dates) are calculated from those data for subsamples...
Mineralogy, strontium (87Sr/86Sr), oxygen (18O/16O) and carbon (13C/12C) isotope composition, elemental concentrations, and U-Th disequilibrium ages for travertine deposits from various locations in Yellowstone National Park, USA
Chemical changes in hot springs, as recorded by thermal waters and their mineral deposits, provide a window into the evolution of Yellowstone’s postglacial hydrothermal system. Travertine precipitated from thermal waters provide a record of chemical changes through time because they can be dated using U-series disequilibrium geochronology. These temporal data, along with measured...
Elemental and Strontium Isotopic Composition of Select Central Plateau and Upper Basin Member Rhyolites, Yellowstone Plateau Volcanic Field
The Yellowstone Plateau Volcanic field consists of lavas from the last two million years. The most recent volcanic units are the Central Plateau Member and the older Upper Basin Member rhyolites (Christiansen, 2001). Investigations into the elemental and isotopic composition of these lavas can provide insight into the recent volcanic history of the different eruptive episodes and provide...
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...
Sr and U concentrations and radiogenic isotope compositions (87Sr/86Sr, 234U/238U) of thermal waters, streamflow, travertine, and rock samples along with U-Th disequilibrium ages for travertine deposits from various locations in Yellowstone National Park,
This data provides locations and technical specifications of legacy and current versions of the United States Wind Turbines database. Almost all of which are utility-scale. Utility-scale turbines are ones that generate power and feed it into the grid, supplying a utility with energy. They are usually much larger than turbines that would feed a homeowner or business. Each release...
Strontium and uranium isotopic compositions (87Sr/86Sr and 234U/238U) of mid- to late-Holocene lacustrine sediments from Lower Pahranagat Lake, Pahranagat National Wildlife Refuge, Lincoln County, Nevada
This data release includes a table of concentrations (Sr, U) and radiogenic-isotope compositions (87Sr/86Sr, 234U/238U) for samples of modern lake water as well as a table of isotopic compositions (87Sr/86Sr and 234U/238U) for carbonate-rich samples from a 12.4-m-long composite core of lacustrine sediment from Lower Pahranagat Lake in southeastern Nevada, USA. Stratigraphic and...
Sr concentrations and 87Sr/86Sr data used to determine the Sr-chronostratigraphic age of sirenian fossils on Santa Rosa Island, Channel Islands National Park, California, USA
This data release includes a table of Sr concentrations and 87Sr/86Sr data used to evaluate primary seawater isotope compositions of marine invertebrate shell material used to estimate the Sr-chronostratigraphic age of sediments hosting early Miocene sirenian fossils on Santa Rosa Island of the Channel Island National Park, Ventura County, California
Database for the geologic map of the upper Santa Cruz River basin, southern Arizona
This digital publication contains the database, base maps, and style files used to build the geologic map of the upper Santa Cruz River basin in southern Arizona published in U.S. Geological Survey Scientific Investigations Map 3490 (Page and others, 2023). Shapefiles are also included for the user’s convenience. In the database, there are polygon features outlining the map units and...
Sr-, U-, H- and O-isotope data used to evaluate water sources in the Potrero Creek Wetlands, Upper Santa Cruz Basin, southern Arizona, USA
This data release includes a table of 87Sr/86Sr, 234U/238U, δ2H, and δ18O isotope data used to evaluate groundwater- and surface-water-sources contributing to water in perennial wetlands near the mouth of Potrero Creek within the Upper Santa Cruz Basin near Nogales, AZ. Interpretations of those data are discussed in the pamphlet accompanying the USGS Scientific Investigations Map SIM...
Uranium- and thorium-isotope data used to estimate uranium-series ages of Pleistocene lake deposits in the Lake Manix basin, Mojave Desert, California
This data release contains numerical U- and Th-isotopic data used to calculate uranium-series age estimates and initial 234U/238U activity ratios for samples of carbonate-rich clast coatings, oncoidal tufa rinds, calcite-replaced rhizoliths, carbonate nodules, and ostracod shells from sites associated with different lake levels of paleo Lake Manix near Barsow, CA. In addition, measured U...
Geologic map and hydrogeologic investigations of the upper Santa Cruz River basin, southern Arizona
This report includes an updated geologic map and cross sections of the upper Santa Cruz River basin, southern Arizona. The map and cross sections describe the geometry, thickness, and structure of the Miocene to Holocene units which form the main aquifers in the basin. The report also includes results of new hydrogeologic studies including (1) mapping and defining depth to bedrock based...
Geologic map of the Fort Morgan 7.5' quadrangle, Morgan County, Colorado
The Fort Morgan 7.5′ quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the late Pliocene to the...
Geologic map of the Weldona 7.5' quadrangle, Morgan County, Colorado
The Weldona 7.5′ quadrangle is located on the semiarid plains of northeastern Colorado, along the South Platte River corridor where the river has incised into Upper Cretaceous Pierre Shale. The Pierre Shale is largely covered by surficial deposits that formed from alluvial, eolian, and hillslope processes operating in concert with environmental changes from the Pleistocene to the present...
Geologic map of the Masters 7.5' quadrangle, Weld and Morgan Counties, Colorado
The Masters 7.5' quadrangle is located along the South Platte River corridor on the semiarid plains of eastern Colorado and contains surficial deposits that record alluvial, eolian, and hillslope processes that have operated in concert with environmental changes from Pleistocene to present time. The South Platte River, originating high in the Colorado Front Range, has played a major role...
Geologic and geophysical maps of the Las Vegas 30' x 60' quadrangle, Clark and Nye counties, Nevada, and Inyo County, California
Las Vegas and Pahrump are two of the fastest growing cities in the US, and the shortage of water looms as among the greatest future problems for these cities. These new maps of the Las Vegas 30 x 60-minute quadrangle provide a geologic and geophysical framework and fundamental earth science database needed to address societal issues such as ground water supply and contamination, surface...
Geologic map of the Mound Spring quadrangle, Nye and Clark Counties, Nevada, and Inyo County, California
The Mound Spring quadrangle, the southwestern-most 7.5' quadrangle of the area of the Las Vegas 1:100,000-scale quadrangle, is entirely within the Pahrump Valley, spanning the Nevada/California State line. New geologic mapping of the predominantly Quaternary materials is combined with new studies of gravity and geochronology in this quadrangle. Eleven predominantly fine-grained units are...
Filter Total Items: 87
Radiogenic strontium- and uranium-isotope tracers of water-rock interactions and hydrothermal flow in the Upper Geyser Basin, Yellowstone Plateau Volcanic Field, USA
Natural radiogenic isotopes (primarily 87Sr/86Sr) from hot springs in the Upper Geyser Basin of the Yellowstone Plateau volcanic field and associated rocks were used to evaluate groundwater flow patterns, water-rock reactions, and the extent of mixing between various groundwater sources. Thermal waters have very low uranium concentrations and 234U/238U activity ratios near 1.0, which...
Authors
James B. Paces, Shaul Hurwitz, Lauren N Harrison, Jacob B. Lowenstern, R. Blaine McCleskey
Clumped isotopes record a glacial-interglacial shift in seasonality of soil carbonate accumulation in the San Luis Valley, southern Rocky Mountains, USA
Clumped isotope paleothermometry using pedogenic carbonates is a powerful tool for investigating past climate changes. However, location-specific seasonal patterns of precipitation and soil moisture cause systematic biases in the temperatures they record, hampering comparison of data across large areas or differing climate states. To account for biases, more systematic studies of...
Authors
Adam M. Hudson, Julia R. Kelson, James B. Paces, Chester A. Ruleman, Katharine W. Huntington, Andrew J. Schauer
Travertine records climate-induced transformations of the Yellowstone hydrothermal system from the late Pleistocene to the present
Chemical changes in hot springs, as recorded by thermal waters and their deposits, provide a window into the evolution of the postglacial hydrothermal system of the Yellowstone Plateau Volcanic Field. Today, most hydrothermal travertine forms to the north and south of the ca. 631 ka Yellowstone caldera where groundwater flow through subsurface sedimentary rocks leads to calcite...
Authors
Lauren N Harrison, Shaul Hurwitz, James B. Paces, Cathy Whitlock, Sara E. Peek, Joseph M. Licciardi
Evaluation of hydrologic processes in the eastern Snake River Plain aquifer using uranium and strontium isotopes, Idaho National Laboratory, eastern Idaho
Waste constituents discharged to the eastern Snake River Plain aquifer at the U.S. Department of Energy (DOE) Idaho National Laboratory (INL) pose risks to the water quality of the aquifer. To understand these risks, the U.S. Geological Survey, in cooperation with the DOE, is conducting geochemical studies to better understand the hydrologic processes at the INL that affect the movement...
Authors
Gordon W. Rattray, James B. Paces
Strontium isotope chronostratigraphic age of a sirenian fossil site on Santa Rosa Island, Channel Islands National Park, California
Fossils in the order Sirenia (family Dugongidae) from Santa Rosa Island, part of Channel Islands National Park in southern California, provide rare temporal and spatial links between earlier and later evolutionary forms of dugongids, and add information about their dispersal into the northeastern Pacific region. Marine sedimentary rocks containing these fossils have characteristics of...
Authors
James B. Paces, Scott A. Minor, Kevin Schmidt, Jonathan N. Hoffman
Climate-driven mid- to late Holocene hydrologic evolution of arid wetlands documented by strontium, uranium, and oxygen isotopes from Lower Pahranagat Lake, southern Nevada, USA
Lacustrine carbonates in a 12.4-m-long core from Lower Pahranagat Lake (LPAH), southern Nevada, indicate that radiogenic isotopes of Sr and U (87Sr/86Sr and 234U/238U) preserve evidence of past variations in water sources and evolving hydrologic conditions. Sr and U isotope compositions in LPAH carbonates fall within the range defined by the three primary groundwater sources in...
Authors
Kevin M. Theissen, James B. Paces
The Coles Hill uranium deposit, Virginia, USA: Geology, geochemistry, geochronology, and genetic model
The Coles Hill uranium deposit with an indicated resource of about 130 million lbs. of U3O8 is the largest unmined uranium deposit in the United States. The deposit is hosted in the Taconian (approximately 480 – 450 Ma) Martinsville igneous complex, which consists of the Ordovician Leatherwood Granite (granodiorite) and Silurian Rich Acres Formation (diorite). The host rock was...
Authors
Susan M. Hall, J.S. Beard, Christopher J. Potter, R.J. Bodnar, Leonid A. Neymark, James B. Paces, Craig A. Johnson, G.N. Breit, Robert A. Zielinski, G. J. Aylor
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
The US Environmental Protection Agency's short-term freshwater effluent test methods include a fish (Pimephales promelas), a cladoceran (Ceriodaphnia dubia), and a green alga (Raphidocelis subcapitata). There is a recognized need for additional taxa to accompany the three standard species for effluent testing. An appropriate additional taxon is unionid mussels because mussels are widely...
Authors
Marith C. Reheis, David Miller, James B. Paces, Charles Gifford Oviatt, Joanna R. Redwine, Darrell S. Kaufman, Jordon E. Bright, Elmira Wan
Dating silica sinter (geyserite): A cautionary tale
We describe a new effort to date hydrothermal silica sinter deposits (geyserite) from the Upper Geyser Basin of Yellowstone National Park using 14C of co-deposited organic matter, U-series and cosmogenic 10Be methods. A majority of the samples were collected from stratigraphic sections, mainly at Riverside, Giant, and Castle Geysers. Ages obtained from 41 14C analyses range from modern...
Authors
Dakota Churchill, Michael Manga, Shaul Hurwitz, Sara E. Peek, Joseph M. Licciardi, James B. Paces
Hydrothermal activity in the southwest Yellowstone Plateau Volcanic Field
In the past two decades, the U.S. Geological Survey and the National Park Service have studied hydrothermal activity across the Yellowstone Plateau Volcanic Field (YPVF) to improve the understanding of the magmatic-hydrothermal system and to provide a baseline for detecting future anomalous activity. In 2017 and 2018 we sampled water and gas over a large area in the southwest YPVF and...
Authors
Shaul Hurwitz, R. Blaine McCleskey, Deborah Bergfeld, Sara E. Peek, David Susong, David A. Roth, Jefferson Hungerford, Erin B White, Lauren N Harrison, Behnaz Hosseini, R. Greg Vaughan, Andrew G. Hunt, James B. Paces
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
The Tecopa basin in eastern California was a terminal basin that episodically held lakes during most of the Quaternary until the basin and its modern stream, the Amargosa River, became tributary to Death Valley. Although long studied for its sedimentology, diagenesis, and paleomagnetism, the basin’s lacustrine and paleoclimate history has not been well understood, and conflicting...
Authors
Marith C. Reheis, John Caskey, Jordon E. Bright, James B. Paces, Shannon A. Mahan, Elmira Wan
300,000 yr history of water-table fluctuations at Wind Cave, South Dakota, USA—Scale, timing, and groundwater mixing in the Madison Aquifer
Deposits of calcite coating the lower passages of Wind Cave in the southern Black Hills of South Dakota were precipitated under phreatic conditions. Data from samples associated with a new cave survey and hydrologic studies indicate that past water tables within Wind Cave reached a maximum height of 45 m above modern levels but were mostly confined to 25 m or less. Uranium-series ages...
Authors
James B. Paces, Margaret V. Palmer, Arthur N. Palmer, Andrew J. Long, Matthew P. Emmons
Non-USGS Publications**
Paces, J.B., Nakai, S., Neal, C.R., Taylor, L.A., Halliday, A.N., and Lee, D-C, 1991, A Sr and Nd isotopic study of Apollo 17 high-Ti basalts: resolution of ages, evolution of magmas, and origins of source heterogeneities: Geochimica et Cosmochimica Acta, v. 55, p. 2025-2043.
Neal, C.R., Taylor, L.A., Davidson, J.P., Holden, P., Halliday, A.N., Paces, J.B., Clayton, R.N., and Mayeda, T.K., 1990, Eclogites with oceanic crustal and mantle signatures from the Bellsbank Kimberlite, South Africa, Part II: Radiogenic isotopes and geochemical evolution: Earth and Planetary Science Letters, v. 99, p. 362-379.
Davis, D.W., and Paces, J.B., 1990, Time resolution of geological events on the Keweenaw Peninsula and implications for development of the Midcontinent Rift system: Earth and Planetary Science Letters, v. 97, p. 54-64.
Paces, J.B., and Bell, K., 1989, Non-depleted sub-continental mantle beneath the Superior Province of the Canadian Shield: Nd-Sr isotopic and trace element evidence from Midcontinent Rift basalts: Geochimica et Cosmochimica Acta, v. 53, p. 2023-2035.
Zolensky, M.E., Sylvester, P.J., and Paces, J.B., 1988, Origin and significance of blue coloration in quartz from Llano Rhyolite (Llanite), north-central Llano County, Texas: American Mineralogist, v. 73, p. 313-323.
Bornhorst, T.J., Kalliokoski, J., and Paces, J.B., 1986, The Keweenaw Native-Copper District, in Brown, A.C., Kirkham, R.V. (eds.), Proterozoic Sediment-hosted Stratiform Copper Deposits of Upper Michigan and Belt Supergroup of Idaho and Montana: Geological Association of Canada/Mineralogical Association of Canada/Canadian Geophysical Union Joint Annual Meeting, Ottawa '86, Field Trip 1 Guidebook, p. 21-36.
McDowell, S.D., and Paces, J.B., 1985, Carbonate alteration minerals in the Salton Sea geothermal system, California, USA: Mineral Magazine, v. 49, p. 469-479.
Wilson, M.L., Paces, J.B., and Ruotsala, A.P., 1984, Fluorapatite from the King Lithia mine, Custer County, South Dakota: Mineral Record v. 15, p. 361-366.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.