Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
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
Developing landslide chronologies using landslide-dammed lakes in the Oregon Coast Range
The Oregon Coast Range is a dynamic landscape that is continually shaped by shallow and deep-seated landslides that can have disastrous consequences to infrastructure and human lives. Searching for evidence of potentially coseismic mass wasting is incredibly difficult, particularly when historical observations are limited. Landslide-dammed lakes with submerged “ghost forests” in the Oregon Coast R
Authors
Logan Wetherell, William Struble, Sean Richard LaHusen
Synchronous emplacement of the anorthosite xenolith-bearing Beaver River diabase and one of the largest lava flows on Earth
New geochronologic and paleomagnetic data from the North American Midcontinent Rift (MCR) reveal the synchronous emplacement of the Beaver River diabase, the anorthosite xenoliths within it, and the Greenstone Flow—one of the largest lava flows on Earth. A U-Pb zircon date of 1091.83 0.21 Ma (2) from one of the anorthosite xenoliths is consistent with the anorthosite cumulate forming as part of t
Authors
Yiming Zhang, Nicholas L. Swanson-Hysell, Mark D. Schmitz, James D. Jr. Miller, Margaret Susan Avery
Geologic framework of Mount Diablo, California
The basic stratigraphic and structural framework of Mount Diablo is described using a revised geologic map, gravity data, and aeromagnetic data. The mountain is made up of two distinct stratigraphic assemblages representing different depocenters that were juxtaposed by ~20 km of late Pliocene and Quaternary right-lateral offset on the Greenville-Diablo-Concord fault. Both assemblages are composed
Authors
Russell Graymer, Victoria Langenheim
Global biotic events evident in the Paleogene marine strata of the eastern San Francisco Bay area, California
Paleogene marine strata in the eastern San Francisco Bay area are exposed in discontinuous outcrops in the various tectonic blocks. Although there are many missing intervals, the strata were previously thought to span most of the Paleocene and Eocene. Revision of biochronology and calibration to the international time scale as well as to the global oxygen isotope curve and sea-level curves indicat
Authors
Kristin McDougall-Reid
Redefining the age of the lower Colorado River, southwestern United States: Comment
No abstract available.
Authors
Rebecca J. Dorsey, Gary J. Axen, Martin J. Grove, Bernard Housen, George Jefferson, Kristin McDougall-Reid, Lyndon Murray, Michael E. Oskin, Tom Peryam, Jolante W. van Wijk, Elaine Young
Redefining the age of the lower Colorado River, southwestern United States: Reply
Crow et al. (2021) report new geochronologic and paleomagnetic data indicating that the lower Colorado River (CR) became integrated to the proto–Gulf of California (GOC) between 4.8 and 4.62 Ma instead of at ca. 5.3 Ma, as suggested by Dorsey et al. (2007, 2018). Dorsey et al. (2021) dispute this new chronology but offer no alternative explanation for one of the key data sets requiring it, new det
Authors
Ryan S. Crow, Jonathan Schwing, Karl Karlstrom, Matt Heizler, Philip Pearthree, Kyle House, Shannon Dulin, Susane Janecke, Mark E. Stelten, Laurie Crossey