Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Interpretation of low‐temperature thermochronometer ages from tilted normal fault blocks
Low‐temperature thermochronometry is widely used to measure the timing and rate of slip on normal faults. Rates are often derived from suites of footwall thermochronometer samples, but regression of age vs. structural depth fails to account for the trajectories of samples during fault slip. We demonstrate that in rotating fault blocks, regression of age‐depth data is susceptible to significant err
Authors
Samuel Johnstone, Joseph Colgan
Large hydromagmatic eruption related to Fernandina Volcano’s 1968 caldera collapse—Deposits, landforms, and ecosystem recovery
The hydromagmatic eruption that immediately preceded the 1968 caldera collapse of Fernandina Volcano, Galápagos, which had a volcano explosivity index (VEI) of 4, offers a case study of powerful eruptions where basaltic magma interacts with caldera-ponded water. The 4-d-long hydromagmatic eruption sequence records an early stage and a small fraction of the volume of magmatic withdrawal that led th
Authors
Keith A. Howard, Tom Simkin, Dennis J. Geist, Godfrey Merlen, Bruce Nolf
Thermally induced fracture of macroscale surficial granite sheets
Geologically diverse landforms around the world show indications of energetic macroscale fracture. These fractures are sometimes displayed dramatically as so-called “A-tents”, whereby relatively thin rock sheets push upwards and fracture, forming tent-like voids beneath the ruptured sheets. The origin and formation of such features has been a topic of considerable interest and analysis for over a
Authors
Brian D. Collins, Greg M. Stock, Martha C. Eppes
Ice-sheet modulation of deglacial North American monsoon intensification
The North American monsoon, the dominant source of rainfall for much of the arid US Southwest, remains one of the least understood monsoon systems. The late Pleistocene evolution of this monsoon is poorly constrained, largely because glacial changes in winter rainfall obscure summer monsoon signatures in many regional proxy records. Here, we develop deglacial records of monsoon strength from isoto
Authors
Tripti Bhattacharya, Jessica E. Tierney, Jason A. Addison, James W. Murray
Understanding how microbiomes influence the systems they inhabit
Translating the ever-increasing wealth of information on microbiomes (environment, host, or built environment) to advance the understanding of system-level processes is proving to be an exceptional research challenge. One reason for this challenge is that relationships between characteristics of microbiomes and the system-level processes they influence are often evaluated in the absence of a robus
Authors
E.K. Hall, E. S. Bernhardt, R.L. Bier, M.A. Bradford, C.M. Boot, J.B. Cotner, P.A. del Giorgio, S.E. Evans, E.B.; Graham, S.E. Jones, J.T. Lennon, Kenneth J. Locey, D. Nemergut, B. Osborne, J.D. Rocca, J.S. Schimel, Mark Waldrop, M.W. Wallenstein
Potential toxicity of dissolved metal mixtures (Cd, Cu, Pb, Zn) to early life stage white sturgeon (Acipenser transmontanus) in the Upper Columbia River, Washington, United States
The Upper Columbia River (UCR) received historical releases of smelter waste resulting in elevated metal concentrations in downstream sediments. Newly hatched white sturgeon hide within the rocky substrate at the sediment–water interface in the UCR for a few weeks before swim-up. Hiding behavior could expose them to metal contaminants, and metal toxicity could contribute to population declines in
Authors
Laurie S. Balistrieri, Christopher A. Mebane, Stephen E. Cox, Holly J. Puglis, Robin Calfee, Ning Wang
Bedrock mapping and seismic hazard assessment at Gold Basin landslide, Washington
The Gold Basin landslide is located along the South Fork Stillaguamish River, within the Mount Baker-Snoqualmie National Forest in western Washington State. Recent concerns related to slope stability after the 2014 State Route 530 Landslide near Oso, Washington, forced the closure of the U.S. Forest Service Gold Basin Campground in May of 2014. In addition to safety concerns for National Forest vi
Authors
Lydia M. Staisch
Geology and geologic history: Overview of the geology of the San Francisco Bay region
The geology of San Francisco and the surrounding northern and central California area has played a pivotal role in the development of our understanding of Earth processes, especially the process of tectonic accretion at a continental margin and the development of transform plate margins. The Franciscan Complex, which underlies most (or perhaps all) of the City and County of San Francisco, is wide
Authors
Russell Graymer
Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations
During the last deglaciation (19,000–9,000 years ago), atmospheric CO2increased by about 80 ppm. Understanding the mechanisms responsible for this change is a central theme of palaeoclimatology, relevant for predicting future CO2 transfers in a warming world. Deglacial CO2 rise hypothetically tapped an accumulated deep Pacific carbon reservoir, but the processes remain elusive as they are undercon
Authors
Jianghui Du, Brian Haley, Alan Mix, Maureen Walczak, Summer K. Praetorius
Global and Arctic climate sensitivity enhanced by changes in North Pacific heat flux
Arctic amplification is a consequence of surface albedo, cloud, and temperature feedbacks, as well as poleward oceanic and atmospheric heat transport. However, the relative impact of changes in sea surface temperature (SST) patterns and ocean heat flux sourced from different regions on Arctic temperatures are not well constrained. We modify ocean-to-atmosphere heat fluxes in the North Pacific and
Authors
Summer K. Praetorius, Maria A. Rugenstein, Geeta Persad, Ken Caldeira
Hunting for landslides from Cascadia's great earthquakes
No abstract available.
Authors
Jonathan P. Perkins, Joshua J. Roering, William J. Burns, William Strubel, Bryan A. Black, Kevin Schmidt, Alison Duvall, Nancy C. Calhoun
Carving Grand Canyon’s inner gorge: A test of steady incision versus rapid knickzone migration
A recent study posits that much of the 240-m-deep inner gorge of Grand Canyon was carved between 500 and 400 ka via passage of a migrating knickzone with incision rates of ~1600 m/Ma during that time period; this was based on dating of a ca. 500 ka travertine deposit perched on the rim of the inner gorge, near Hermit Rapid, and a ca. 400 ka travertine drape that extends to within 60 m of river lev
Authors
Ryan S. Crow, Karl E. Karlstrom, Laura J. Crossey, Victor Polyak, Yemane Asmerom, William C. McIntosh