Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Environmental evolution of peat in the Sacramento – San Joaquin Delta (California) during the Middle and Late Holocene as deduced from pollen, diatoms and magnetism
We studied the sequence of climatic and hydrological events associated with the formation of peat during the Holocene, using pollen, diatoms and environmental magnetism from peat cores at three locations in the Sacramento-San Joaquin Delta of California: Browns Island, Franks Wetland and Webb Track Levee. Our data show that peat first formed under relatively dry conditions in a freshwater environm
Authors
Irina Delusina, Scott W. Starratt, Kenneth L Verosub
Understanding rates of change: A case study using fossil pollen records from California to assess the potential for and challenges to a regional data synthesis
Insights into the rates at which ecosystems and vegetation respond to a changing climate is fundamental to anticipating impacts of projected climate change. Characterization of vegetation change over millennia to centuries has potential to make an important contribution toward this goal, and regional scale syntheses of fossil pollen data can provide the foundation for this understanding. However,
Authors
Lysanna Anderson, David Wahl, T. Bhattacharya
An 11,300 yr record of paleoclimatology and paleoceanography of the central California coast in a gravity core from Pioneer Seamount
Diatom, pollen, silicoflagellate, and biogenic opal analyses from a 155 cm-long gravity core from Pioneer Seamount, offshore Santa Cruz, California (PS1410-06 GC, latitude 37.3°N, longitude 123.4°W, water depth 2165 m) are compiled for the last ~11,300 years and compared with those of ODP 1019 and TN062-O550 from northern California. The relative abundance record of the subtropical diatom Fragilar
Authors
John A. Barron, Jason A. Addison, Linda E. Heusser, David Bukry, Valerie Evelyn Schwartz, Amy Wagner
The source, fate, and transport of arsenic in the Yellowstone hydrothermal system - An overview
The Yellowstone Plateau Volcanic Field (YPVF) contains >10,000 thermal features including hot springs, pools, geysers, mud pots, and fumaroles with diverse chemical compositions. Arsenic (As) concentrations in YPVF thermal waters typically range from 0.005 to 4 mg/L, but an As concentration of 17 mg/L has been reported. Arsenic data from thermal springs, outflow drainages, rivers, and from volcani
Authors
R. Blaine McCleskey, D. Kirk Nordstrom, Shaul Hurwitz, Daniel R. Colman, David A. Roth, Madeline Oxner Johnson, Eric S. Boyd
Geochronologic, isotopic, and geochemical data from pre-Cretaceous plutonic rocks in the Lane Mountain area, San Bernardino County, California
Pre-Cretaceous, predominantly dioritic plutonic rocks in the Lane Mountain area, California, intrude metasedimentary and metavolcanic rocks considered part of the El Paso terrane. New geochronologic (uranium-lead zircon), geochemical, and isotopic data provide a reliable basis for dividing these pre-Cretaceous plutonic rocks into two mappable suites of Permian–Triassic and Late Jurassic ages. The
Authors
Paul Stone, Howard J. Brown, M. Robinson Cecil, Robert J. Fleck, Jorge A. Vazquez, John A. Fitzpatrick
Historical and paleoflood analyses for probabilistic flood-hazard assessments—Approaches and review guidelines
Paleoflood studies are an effective means of providing specific information on the recurrence and magnitude of rare and large floods. Such information can be combined with systematic flood measurements to better assess the frequency of large floods. Paleoflood data also provide valuable information about the linkages among climate, land use, flood-hazard assessments, and channel morphology. This d
Authors
Tessa M. Harden, Karen R. Ryberg, Jim E. O'Connor, Jonathan M. Friedman, Julie E. Kiang
Impacts of climate change on groundwater availability and spring flows: Observations from the highly productive Medicine Lake Highlands/Fall River Springs Aquifer System
Medicine Lake Highlands/Fall River Springs Aquifer System, located in northeastern California, is home to some of the largest first-order springs in the United States. This work assesses the likely effects of projected climate change on spring flow. Four anticipated climate futures (GFDL A2, GFDL B1, CCSM4 rcp 8.5, CNRM rcp 8.5) for California, which predict a range of conditions (generally warmin
Authors
Lauren K Mancewicz, L. Davisson, Shawn J Wheelock, Erick R. Burns, Simon R. Poulson, Scott W. Tyler
Origin of the J-M Reef and Lower Banded series, Stillwater Complex, Montana, USA
The origin and parental magma for layered cumulates in the Lower Banded series (LBS) and the J-M Reef Pd-Pt deposit of the Stillwater Complex remains poorly constrained. We present whole-rock lithogeochemistry and mineral chemistry from LBS rocks collected from drill holes and surface samples from the Mountain View area of the complex that in total span nearly the entirety of the LBS stratigraphy.
Authors
Michael Jenkins, James E. Mungall, Michael L. Zientek, Gelu Costin, Zhuo-sen Yao
Mineral deposit discovery order and three-part quantitative assessments
Larger oil pools tending to be discovered earlier in an exploration play suggests the same pattern might exist for mineral deposits and could be used in predicting sizes of undiscovered deposits in mineral assessments. The volume of individual petroleum pools is highly correlated with surface projection area of pools in basins. The gradual additions to individual oil pool reserves over time adds t
Authors
Donald A. Singer, Michael L. Zientek
Bottom-up and top-down control on hydrothermal resources in the Great Basin: An example from Gabbs Valley, Nevada
The Great Basin in the western United States hosts various hydrothermal systems, including both active geothermal systems and ancient systems preserved as mineral deposits. New magnetotelluric and structural geologic data were collected in the Gabbs Valley area of western Nevada to demonstrate the advantage of imaging the full crustal column below known hydrothermal systems. Three-dimensional mode
Authors
Jared R. Peacock, Drew L. Siler
Testing models of Laramide orogenic initiation by investigation of Late Cretaceous magmatic-tectonic evolution of the central Mojave sector of the California arc
The Mojave Desert region is in a critical position for assessing models of Laramide orogenesis, which is hypothesized to have initiated as one or more seamounts subducted beneath the Cretaceous continental margin. Geochronological and geochemical characteristics of Late Cretaceous magmatic products provide the opportunity to test the validity of Laramide orogenic models. Laramide-aged plutons are
Authors
R.C Economos, Andrew P. Barth, J.L. Wooden, S. R Paterson, Brody Friesenhahn, B.A Weigand, J.L. Anderson, J.L. Roell, E.F. Palmer, A.J. Ianno, Keith A. Howard
The Boreal-Arctic Wetland and Lake Dataset (BAWLD)
Methane emissions from boreal and arctic wetlands, lakes, and rivers are expected to increase in response to warming and associated permafrost thaw. However, the lack of appropriate land cover datasets for scaling field-measured methane emissions to circumpolar scales has contributed to a large uncertainty for our understanding of present-day and future methane emissions. Here we present the Borea
Authors
David Olefeldt, Mikael Hovemyr, M.A. Kuhn, D Bastviken, T.J. Bohn, J. Connolly, P.M. Crill, E.S. Euskirchen, S.A. Finkelstein, H. Genet, G. Grosse, L.I. Harris, L. Heffernan, M. Helbig, G. Hugelium, R. Hutchins, S. Juutinen, M.J. Lara, A. Malhotra, Kristen L. Manies, A.D. McGuire, S.M. Natali, J. A. O'Donnell, F-J.W. Parmentier, A. Rasanen, C. Schaedel, O. Sonnentag, M. Strack, S.E. Tank, C. C. Treat, R.K. Varner, T. Virtanen, J.D. Watts, R.K. Warren