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.
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.
Biography
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
Date published: May 8, 2019
Status: Active 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. This...
Contacts: Amy Gilmer, Leah E Morgan, Ph.D., Michael Cosca, Adam M Hudson, James Paces, Joseph Colgan
Attribution: Community for Data Integration (CDI)
Date published: March 19, 2020
Uranium-, thorium-, strontium-, carbon- and oxygen-isotope data used to evaluate a 300,000-year history of water-table fluctuations at Wind Cave, South Dakota, USA — scale, timing, and groundwater mixing in the Madison Aquifer
Tables of U- and Th-isotopic data used to calculate uranium-series age estimates and initial 234U/238U activity ratios as well as 87Sr/86Sr, δ13C, and δ18O for samples of phreatic speleothems from Wind Cave National Park and U- and Sr-isotopic compositions of waters from the southern Black Hills of South Dakota, USA
Year Published: 2020
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...
Churchill, Dakota M.; Manga, Michael; Hurwitz, Shaul; Peek, Sara; Licciardi, Joseph; Paces, James
Year Published: 2020
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...
Hurwitz, Shaul; McCleskey, R. Blaine; Bergfeld, Deborah; Peek, Sara; Susong, David; Roth, David A.; Hungerford, Jefferson; White, Erin B; Harrison, Lauren; Hosseini, Behnaz; Vaughan, R. Greg; Hunt, Andrew G.; Paces, James
Year Published: 2019
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...
Paces, James; Palmer, Margaret V.; Palmer, Arthur N.; Long, Andrew J.; Emmons, Matthew P.
Year Published: 2019
Multivariate analysis of hydrochemical data for Jewel Cave, Wind Cave, and surrounding areas
Jewel Cave National Monument and Wind Cave National Park in South Dakota contain two of the six longest caves worldwide. These caves contain subterranean lakes that are important points of intersection between the water table of the Madison aquifer and the caves. During 2015 to 2017, several subterranean lakes were discovered in Jewel Cave, which...
Long, Andrew J.; Paces, James B.; Eldridge, William G.Attribution: Washington Water Science Center, Water Resources
Year Published: 2019
Middle Pleistocene formation of the Rio Grande Gorge, San Luis Valley, south-central Colorado and north-central New Mexico, USA: Process, timing, and downstream implications
The Rio Grande is the fourth longest river in North America extending over 3,000 km from the Rocky Mountains to the Gulf of Mexico. The Pleistocene evolution of this river from individual subbasins into a coalesced fluvial system has been long debated. Herein, we constrain the middle Pleistocene evolution of the northernmost and largest Rio Grande...
Ruleman, Chester A.; Hudson, Adam M.; Thompson, Ren A.; Miggins, Daniel P.; Paces, James; Goehring, Brent M.
Year Published: 2019
Calcrete uranium deposits in the Southern High Plains, USA
The Southern High Plains (SHP) is a new and emerging U.S. uranium province. Here, uranyl vanadates form deposits in Pliocene to Pleistocene sandstone, dolomite, and limestone. Fifteen calcrete uranium occurrences are identified; two of these, the Buzzard Draw and Sulfur Springs Draw deposits, have combined in-place resources estimated at about 4...
Hall, Susan; Van Gosen, Bradley S.; Paces, James B.; Zielinski, Robert A.
Year Published: 2018
Disparate perspectives on evidence from the Cerutti Mastodon site: A reply to Braje et al.
The Perspective editorial by Braje, T., T. D. Dillehay, J. M. Erlandson, S. M. Fitzpatrick, D. K. Grayson, V. T. Holliday, R. L. Kelly, R. G. Klein, D. J. Meltzer, and T. C. Rick (2017. “Were Hominins in California ∼130,000 Years Ago?” PaleoAmerica 3 (3): 200–202) takes issue with our argument [Holen, S. R., T. A. Deméré, D. C. Fisher, R...
Holen, Steven R.; Demere, Thomas A.; Fisher, Daniel C.; Fullagar, Richard; Paces, James B.; Jefferson, George T.; Beeton, Jared M.; Rountrey, Adam N.; Holen, Kathleen A.View Citation
Holen, S.R., Deméré, T.A., Fisher, D.C., Fullagar, R., Paces, J.B., Jefferson, G.T., Beeton, J.M, Cerutti, R.A., Rountrey, A.N., Vescera, L. & Holen, K.A., 2018, Disparate perspectives on evidence from the Cerutti Mastodon Site: A reply to Braje et al. PaleoAmerica, vol. 4, issue 1, p. 12-15 https://www.tandfonline.com/doi/abs/10.1080/20555563.2017.1396836
Year Published: 2018
Comment on “The earliest modern humans outside Africa”
Hershkovitz et al. (Reports, 26 January 2018, p. 456) interpreted the Misliya-1 fossil maxilla as evidence of the earliest known anatomically modern human outside Africa. However, the fossil’s reported age of 177,000 to 194,000 years relies on flawed interpretations of uranium-series data. We contend that those data support a minimum age of...
Sharp, Warren D.; Paces, James B.
Year Published: 2018
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...
Berry, Margaret E.; Taylor, Emily M.; Slate, Janet L.; Paces, James B.; Hanson, Paul R.; Brandt, Theodore R.Attribution: Geosciences and Environmental Change Science Center, Groundwater and Streamflow Information Program, Region 7: Upper Colorado Basin
View Citation
Berry, M.E., Taylor, E.M., Slate, J.L., Paces, J.B., Hanson, P.R., and Brandt, T.R., 2018, Geologic map of the Fort Morgan 7.5' quadrangle, Morgan County, Colorado: U.S. Geological Survey Scientific Investigations Map 3408, 2 sheets, scale 1:24,000, https://doi.org/10.3133/sim3408.
Year Published: 2018
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...
Berry, Margaret E.; Taylor, Emily M.; Slate, Janet L.; Paces, James B.; Hanson, Paul R.; Brandt, Theodore R.Attribution: Geosciences and Environmental Change Science Center, Groundwater and Streamflow Information Program, Region 7: Upper Colorado Basin
View Citation
Berry, M.E., Taylor, E.M., Slate, J.L., Paces, J.B., Hanson, P.R., and Brandt, T.R., 2018, Geologic map of the Weldona 7.5′ quadrangle, Morgan County, Colorado: U.S. Geological Survey Scientific Investigations Map 3396, 1 sheet, scale 1:24,000, https://doi.org/10.3133/sim3396.
Year Published: 2018
Holen et al. reply
Contrary to our hypothesis that the Cerutti Mastodon (CM) site represents a 130,000-year-old archaeological site, in the accompanying Comment Ferraro et al. argue that the site formed through ‘common’ geological and taphonomic processes. As a source for the cobbles that we interpreted as hammerstones and anvils, they postulate a...
Holen, Steven R.; Deméré, Thomas A.; Fisher, Daniel C.; Fullagar, Richard; Paces, James B.; Jefferson, George T.; Beeton, Jared M.; Cerutti, Richard A.; Rountrey, Adam N.; Vescera, Lawrence; Holen, Kathleen A.Attribution: Geosciences and Environmental Change Science Center, Groundwater and Streamflow Information Program, Region 7: Upper Colorado Basin
View Citation
Holen, S.R., Deméré, T.A., Fisher, D.C., Fullagar, R., Paces, J.B., Jefferson, G.T., Beeton, J.M, Cerutti, R.A., Rountrey, A.N., Vescera, L. & Holen, K.A., 2018, Holen et al. reply (replying to J.V. Ferraro et al., Nature 554, 10.1038/nature25165). Nature 554, E3, https://doi.org/10.1038/nature25166
Year Published: 2018
Broken bones and hammerstones at the Cerutti Mastodon site: A reply to Haynes
Haynes [2017 “The Cerutti Mastodon.” PaleoAmerica 3 (3): 196–199] criticizes numerous aspects of our analysis of the Cerutti Mastodon (CM) site, but central among his points is the claim that heavy equipment broke the bones and stones that we interpret as evidence of ancient human activity. This notion can be discounted primarily because...
Holen, Steven R.; Deméré, Thomas A.; Fisher, Daniel C.; Fullagar, Richard; Paces, James B.; Jefferson, George T.; Beeton, Jared M.; Rountrey, Adam N.; Holen, Kathleen A.Attribution: Geosciences and Environmental Change Science Center, Groundwater and Streamflow Information Program, Region 7: Upper Colorado Basin
View Citation
Holen, S.R., Deméré, T.A., Fisher, D.C., Fullagar, R., Paces, J.B., Jefferson, G.T., Beeton, J.M, Cerutti, R.A., Rountrey, A.N., Vescera, L. & Holen, K.A., 2017, Broken bones and hammerstones at the Cerutti Mastodon Site: A reply to Haynes. PaleoAmerica, vol. 4, issue 1, p. 8-11, https://doi.org/10.1080/20555563.2017.1396835
Pre-USGS Publications
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.
The Keweenaw Native-Copper District
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.
Fluorapatite from the King Lithia mine, Custer County, South Dakota
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.
Date published: July 20, 2020
How old are Yellowstone's large geysers? We don't exactly know!
It seems like a simple question: how old is a geyser? We know that all of Yellowstone’s current geysers formed after the last glaciers scoured the land surface about 15,000 years ago. But what happened since that time?