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
Late Quaternary history of Fortymile Wash in the area near the H-road crossing
Secondary minerals record past percolation flux at Yucca Mountain, Nevada
U-Pb age evidence for long-term stability of the unsaturated zone at Yucca Mountain
Neogene to Quaternary U-Th-Pb geochronology using opal, Yucca Mountain, Nevada, USA
Inferences for Yucca Mountain unsaturated-zone hydrology from secondary minerals
Anomalous groundwater 234U/238U beneath Yucca Mountain: Evidence for local recharge?
The implication of a perched-water system based on USW WT-24 hydrochemistry
Paleoseismic investigations of Stagecoach Road Fault, southeastern Yucca Mountain, Nye County, Nevada
"Overview of calcite/opal deposits at or near the proposed high-level nuclear waste site, Yucca Mountain, Nevada, USA: pedogenic, hypogene, or both" by C.A. Hill, Y.V. Dublyansky, R.S. Harmon, C.M. Schluter
Preliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary faults, eastern Yucca Mountain
Precise U‐Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System
Late quaternary history and uranium isotopic compositions of ground water discharge deposits, Crater Flat, Nevada
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
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Filter Total Items: 85
Late Quaternary history of Fortymile Wash in the area near the H-road crossing
No abstract available.AuthorsScott C. Lundstrom, James B. Paces, Shannon A. MahanSecondary minerals record past percolation flux at Yucca Mountain, Nevada
No abstract available.AuthorsBrian D. Marshall, James B. Paces, Leonid A. Neymark, J. F. Whelan, Zell E. PetermanU-Pb age evidence for long-term stability of the unsaturated zone at Yucca Mountain
No abstract available.AuthorsLeonid A. Neymark, Y. V. Amelin, James B. Paces, Zell E. PetermanNeogene to Quaternary U-Th-Pb geochronology using opal, Yucca Mountain, Nevada, USA
No abstract available.AuthorsLeonid A. Neymark, James B. Paces, Yu. V. AmelinInferences for Yucca Mountain unsaturated-zone hydrology from secondary minerals
No abstract available.AuthorsJames B. Paces, Leonid A. Neymark, Brian D. Marshall, J. F. Whelan, Zell E. PetermanAnomalous groundwater 234U/238U beneath Yucca Mountain: Evidence for local recharge?
No abstract available.AuthorsJames B. Paces, K. R. Ludwig, Zell E. Peterman, Leonid A. Neymark, J. M. KenneallyThe implication of a perched-water system based on USW WT-24 hydrochemistry
No abstract available.AuthorsGary L. Patterson, Zell E. Peterman, James B. PacesPaleoseismic investigations of Stagecoach Road Fault, southeastern Yucca Mountain, Nye County, Nevada
No abstract available.AuthorsC. M. Menges, J.A. Oswald, J. A. Coe, S.C. Lundstrom, J.B. Paces, S. A. Mahan, Beth Widmann, Michele Murray"Overview of calcite/opal deposits at or near the proposed high-level nuclear waste site, Yucca Mountain, Nevada, USA: pedogenic, hypogene, or both" by C.A. Hill, Y.V. Dublyansky, R.S. Harmon, C.M. Schluter
No abstract available.AuthorsJohn S. Stuckless, Brian D. Marshall, D. T. Vaniman, W. W. Dudley, Zell E. Peterman, James B. Paces, J. F. Whelan, Emily M. Taylor, Richard M. Forester, D. W. O'LearyPreliminary U-series disequilibrium and thermoluminescence ages of surficial deposits and paleosols associated with Quaternary faults, eastern Yucca Mountain
No abstract available.AuthorsJames B. Paces, Christopher M. Menges, B. Wildmann, J. R. Wesling, Charles A. Bush, Kiyoto Futa, H. T. Millard, P. B. Maat, John W. WhitneyPrecise U‐Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System
Precise resolution of the timing of igneous activity is crucial to understanding the dynamic processes associated with continental rifting. Mafic intrusive rocks constitute a major portion of the exposed 1100 Ma (Keweenawan) Midcontinent Rift system in northeastern Minnesota; however, prior to this study, geochronological data were insufficient to allow rigorous interpretation of intrusive historiAuthorsJames B. Paces, James D. MillerLate quaternary history and uranium isotopic compositions of ground water discharge deposits, Crater Flat, Nevada
Three carbonate-rich spring deposits are present near the southern end of Crater Flat, NV, approximately 18 km southwest of the potential high-level waste repository at Yucca Mountain. We have analyzed five samples of carbonate-rich material from two of the deposits for U and Th isotopic compositions. Resulting U-series disequilibrium ages indicate that springs were active at 18 ?? 1, 30 ?? 3, 45AuthorsJames B. Paces, Emily M. Taylor, Charles BushNon-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.
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