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
The paleohydrology of unsaturated and saturated zones at Yucca Mountain, Nevada, and vicinity
Cosmogenic nuclide and uranium-series dating of old, high shorelines in the western Great Basin, USA
Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California
Limited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada
Late pleistocene aggradation and degradation of the lower colorado river: Perspectives from the Cottonwood area and other reconnaissance below Boulder Canyon
Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California
230Th-U dating of surficial deposits using the ion microprobe (SHRIMP-RG): A microstratigraphic perspective
Geochemical and isotopic evaluation of groundwater movement in corrective action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, rev. no.: 0
Testing the concept of drift shadow at Yucca Mountain, Nevada
Impact of quaternary climate on seepage at Yucca Mountain, Nevada
Uranium-series constraints on subrepository water flow at yucca mountain, nevada
Evaluation of groundwater movement in the Frenchman Flat CAU using geochemical and isotopic analysis
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
The paleohydrology of unsaturated and saturated zones at Yucca Mountain, Nevada, and vicinity
Cosmogenic nuclide and uranium-series dating of old, high shorelines in the western Great Basin, USA
Chronology, sedimentology, and microfauna of groundwater discharge deposits in the central Mojave Desert, Valley Wells, California
Limited hydrologic response to Pleistocene climate change in deep vadose zones - Yucca Mountain, Nevada
Late pleistocene aggradation and degradation of the lower colorado river: Perspectives from the Cottonwood area and other reconnaissance below Boulder Canyon
Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California
230Th-U dating of surficial deposits using the ion microprobe (SHRIMP-RG): A microstratigraphic perspective
Geochemical and isotopic evaluation of groundwater movement in corrective action Unit 97: Yucca Flat/Climax Mine, Nevada Test Site, Nevada, rev. no.: 0
Testing the concept of drift shadow at Yucca Mountain, Nevada
Impact of quaternary climate on seepage at Yucca Mountain, Nevada
Uranium-series constraints on subrepository water flow at yucca mountain, nevada
Evaluation of groundwater movement in the Frenchman Flat CAU using geochemical and isotopic analysis
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.