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
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,
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
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
Database for the geologic map of the upper Santa Cruz River basin, southern Arizona
Sr-, U-, H- and O-isotope data used to evaluate water sources in the Potrero Creek Wetlands, Upper Santa Cruz Basin, southern Arizona, USA
Uranium- and thorium-isotope data used to estimate uranium-series ages of Pleistocene lake deposits in the Lake Manix basin, Mojave Desert, California
The Coles Hill uranium deposit, Virginia, USA: Geology, geochemistry, geochronology, and genetic model
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
Dating silica sinter (geyserite): A cautionary tale
Hydrothermal activity in the southwest Yellowstone Plateau Volcanic Field
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
300,000 yr history of water-table fluctuations at Wind Cave, South Dakota, USA—Scale, timing, and groundwater mixing in the Madison Aquifer
Non-USGS Publications**
**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
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,
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
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
Database for the geologic map of the upper Santa Cruz River basin, southern Arizona
Sr-, U-, H- and O-isotope data used to evaluate water sources in the Potrero Creek Wetlands, Upper Santa Cruz Basin, southern Arizona, USA
Uranium- and thorium-isotope data used to estimate uranium-series ages of Pleistocene lake deposits in the Lake Manix basin, Mojave Desert, California
The Coles Hill uranium deposit, Virginia, USA: Geology, geochemistry, geochronology, and genetic model
Geomorphic history of Lake Manix, Mojave Desert, California: Evolution of a complex terminal lake basin
Dating silica sinter (geyserite): A cautionary tale
Hydrothermal activity in the southwest Yellowstone Plateau Volcanic Field
Pleistocene lakes and paleohydrologic environments of the Tecopa basin, California: Constraints on the drainage integration of the Amargosa River
300,000 yr history of water-table fluctuations at Wind Cave, South Dakota, USA—Scale, timing, and groundwater mixing in the Madison Aquifer
Non-USGS Publications**
**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.