Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2383
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
Active virus-host interactions at sub-freezing temperatures in Arctic peat soil
BackgroundWinter carbon loss in northern ecosystems is estimated to be greater than the average growing season carbon uptake and is primarily driven by microbial decomposers. Viruses modulate microbial carbon cycling via induced mortality and metabolic controls, but it is unknown whether viruses are active under winter conditions (anoxic and sub-freezing temperatures).ResultsWe used stable isotope
Authors
Gareth Trubl, Jeffrey A Kimbrel, Jose Liquet-Gonzalez, Erin E. Nuccio, Peter K. Weber, Jennifer Pett-Ridge, Janet K. Jansson, Mark Waldrop, Steve Blazewicz
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
Late Cenozoic paleogeographic reconstruction of the San Francisco Bay Area from analysis of stratigraphy, tectonics, and tephrochronology
The Neogene stratigraphic and tectonic history of the Mount Diablo area is a consequence of the passage of the Mendocino Triple Junction (MTJ) by the San Francisco Bay area between 12 and 6 Ma, volcanism above a slab-window trailing the MTJ, and crustal transpression beginning ~8-6 Ma, when the Pacific Plate and Sierra Nevada microplate began to converge obliquely. Between ~12-6 Ma, parts of the
Authors
Andrei Sarna-Wojcicki
Late Cenozoic tephrochronology of the Mount Diablo area within the evolving plate-tectonic boundary zone of northern California
We present a tephrochronologic/chronostratigraphic database for the Mount Diablo area and greater San Francisco Bay region that provides a spatial and temporal framework for geologic studies in the region, including stratigraphy, paleogeography, tectonics, quantification of earth surface processes, recurrence of natural hazards, and climate change. We identified and correlated 34 tephra layers wit
Authors
Andrei Sarna-Wojcicki, Raymond Sullivan, Alan L. Deino, Laura Walkup, J. Ross Wagner, Elmira Wan
Arc versus river: The geology of the Columbia River Gorge
The Columbia River Gorge is the Columbia River’s long-held yet evolving passage through the volcanic arc of the Cascade Range. The globally unique setting of a continental-scale river bisecting an active volcanic arc at the leading edge of a major plate boundary creates a remarkable setting where dynamic volcanic and tectonic processes interact with diverse and energetic fluvial processes. This th
Authors
Jim E. O'Connor, Ray Wells, Scott E. K. Bennett, Charles M. Cannon, Lydia M. Staisch, James L Anderson, Anthony Francis Pivarunas, Gabriel Wells Gordon, Richard J. Blakely, Mark E. Stelten, Russell C. Evarts