Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2350
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
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
Influence of permafrost type and site history on losses of permafrost carbon after thaw
We quantified permafrost peat plateau and post-thaw carbon (C) stocks across a chronosequence in Interior Alaska to evaluate the amount of C lost with thaw. Macrofossil reconstructions revealed three stratigraphic layers of peat: (1) a base layer of fen/marsh peat, (2) peat from a forested peat plateau (with permafrost) and, (3) collapse-scar bog peat (at sites where permafrost thaw has occurred).
Authors
Kristen L. Manies, Miriam C. Jones, Mark Waldrop, Mary-Catherine Leewis, Christopher C. Fuller, Robert S. Cornman, Kristen Hoefke
Emergent biogeochemical risks from Arctic permafrost degradation
The Arctic cryosphere is collapsing, posing overlapping environmental risks. In particular, thawing permafrost threatens to release biological, chemical and radioactive materials that have been sequestered for tens to hundreds of thousands of years. As these constituents re-enter the environment, they have the potential to disrupt ecosystem function, reduce the populations of unique Arctic wildlif
Authors
Kimberly Miner, Rachel Mackelprang, Juliana D’Andrilli, Arwyn Edwards, Michael J. Malaska, Mark P. Waldrop, Charles E. Miller
The Mount Hood fault zone, active faulting at the crest of the dynamic Cascade Range, north-central Oregon, USA
The Mount Hood fault zone is a N-trending, ~55-km-long zone of active faulting along the western margin of the Hood River graben in north-central Oregon. The Mount Hood fault zone occurs along the crest of the Cascade Range and consists of multiple active fault segments. It is presently unclear how much Hood River graben extension is actively accommodated on the fault zone, and how Cascade intra-a
Authors
Ian Madin, Ashley R. Streig, Scott E. K. Bennett