Publications
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Breaching of strike-slip faults and successive flooding of pull-apart basins to form the Gulf of California seaway from ca. 8–6 Ma
The geologic record of the formation of marine basins during continental rifting is uncommonly preserved. Using GIS-based paleotectonic maps, we show that marine basin formation in the Gulf of California–Salton trough oblique rift (Mexico and the United States) occurred in a stepwise manner as crustal thinning lowered elevations within the Gulf of California Shear Zone, and subsidence along strike
Authors
Paul J. Umhoefer, Michael H. Darin, Scott E. K. Bennett, Lisa A. Skinner, Rebecca J. Dorsey, Michael E. Oskin
Geochemical characterization and modeling of regional groundwater contributing to the Verde River, Arizona between Mormon Pocket and the USGS Clarkdale gage
We use synoptic surveys of stream discharge, stable isotopes, and dissolved noble gases to identify the source of groundwater discharge to the Verde River in central Arizona. The Verde River more than doubles in discharge in Mormon Pocket over a 1.4 km distance that includes three discrete locations of visible spring input to the river and other diffuse groundwater inputs. A detailed study of th
Authors
Kimberly R. Beisner, W. Payton Gardner, Andrew G. Hunt
Advances in sensitivity analysis of uncertainty to changes in sampling density when modeling spatially correlated attributes
A comparative analysis of distance methods, kriging and stochastic simulation is conducted for evaluating their capabilities for predicting fluctuations in uncertainty due to changes in spatially correlated samples. It is concluded that distance methods lack the most basic capabilities to assess reliability despite their wide acceptance. In contrast, kriging and stochastic simulation offer signifi
Authors
Ricardo A. Olea
A revised Triassic stratigraphic framework for the Arctic Alaska Basin
The Triassic Shublik Formation and the Triassic–Jurassic Otuk Formation are partially age-equivalent lithostratigraphic units that were deposited in the Arctic Alaska Basin (AAB). The Shublik Formation represents proximal deposition within the basin, with episodic siliciclastic input, whereas the Otuk Formation was deposited in the distal part of the basin, with significant intervals of mudstone a
Authors
Katherine J. Whidden, Julie A. Dumoulin, William A. Rouse
Understanding and distinguishing reflectance measurements of solid bitumen and vitrinite using hydrous pyrolysis: Implications to petroleum assessment
Solid bitumen is a common organic component of thermally mature shales and typically is identified by embayment against euhedral mineral terminations and by groundmass textures. However, because these textures are not always present, solid bitumen can be easily misidentified as vitrinite. Hydrous-pyrolysis experiments (72 hr, 300°C–360°C) on shale and coal samples show that solid-bitumen reflectan
Authors
Paul C. Hackley, Michael Lewan
Assessment of undiscovered oil and gas resources in the Eagle Ford Group and associated Cenomanian–Turonian Strata, U.S. Gulf Coast, Texas, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey estimated undiscovered, technically recoverable mean resources of 8.5 billion barrels of oil and 66 trillion cubic feet of gas in continuous accumulations in the Upper Cretaceous Eagle Ford Group and associated Cenomanian–Turonian strata in onshore lands of the U.S. Gulf Coast region, Texas.
Authors
Katherine J. Whidden, Janet K. Pitman, Ofori N. Pearson, Stanley T. Paxton, Scott A. Kinney, Nicholas J. Gianoutsos, Christopher J. Schenk, Heidi M. Leathers-Miller, Justin E. Birdwell, Michael E. Brownfield, Lauri A. Burke, Russell F. Dubiel, Katherine L. French, Stephanie B. Gaswirth, Seth S. Haines, Phuong A. Le, Kristen R. Marra, Tracey J. Mercier, Marilyn E. Tennyson, Cheryl A. Woodall
DDT and related compounds in pore water of shallow sediments on the Palos Verdes Shelf, California, USA
For nearly two and a half decades following World War II, production wastes from the world's largest manufacturer of technical DDT (1-chloro-4-[2,2,2-trichloro-1-(4-chlorophenyl)ethyl]benzene) were discharged into sewers of Los Angeles County. Following treatment, the wastes were released via a submarine outfall system to nearshore coastal waters where a portion accumulated in shallow sediments of
Authors
Robert P. Eganhouse, Erica L. DiFilippo, James Pontolillo, William H. Orem, Paul C. Hackley, Brian Edwards
Rapid 3-D analysis of rockfalls
Recent fatal and damaging rockfalls in Yosemite National Park indicate the need for rapid response data collection methods to inform public safety and assist with management response. Here we show the use of multiple-platform remote sensing methods to rapidly capture pertinent data needed to inform management and the public following a several large rockfalls from El Capitan cliff in Yosemite Val
Authors
Greg M. Stock, A. Guerin, Nikita N. Avdievitch, Brian D. Collins, Michel Jaboyedoff
On the petrographic distinction of bituminite from solid bitumen in immature to early mature source rocks
The oil-prone maceral bituminite (and its equivalents: ‘amorphous organic matter’, ‘sapropelinite’, ‘amorphinite’, etc.) converts to petroleum during thermal maturation of source rocks, resulting in formation of a mobile saturate-rich hydrocarbon and a polar-rich residue of solid bitumen. Evidence of this transition is preserved in immature to early mature source rocks (e.g., Alum, Bakken, Kimmeri
Authors
Paul C. Hackley, Brett J. Valentine, Javin J. Hatcherian
Against the current— The Mojave River from sink to source: The 2018 Desert Symposium field trip road log
The Mojave River evolved over the past few million years by “fill and spill” from upper basins near its source in the Transverse Ranges to lower basins. Each newly “spilled into” basin in the series? sustained a long-lived lake but gradually filled with Mojave River sediment, leading to spill to a yet lower elevation? basin. The Mojave River currently terminates at Silver Lake, near Baker, CA, but
Authors
David M. Miller, R.E. Reynolds, Krishangi D. Groover, David C. Buesch, H. J. Brown, Geoffrey Cromwell, Jill N. Densmore, A.L. Garcia, D. Hughson, J.R. Knott, Jeffrey E. Lovich
Multiple stacked plays to drive continued Permian development
The exploitation of unconventional (continuous) resource plays with horizontal drilling and fracturing techniques continues to spur renewed development in mature producing basins in the US. The Permian basin of west Texas has emerged as a particularly strong prospect due to the potential for multiple stacked resource plays in formations such as the Wolfcamp shale and Spraberry and Bone Spring form
Authors
Kristen R. Marra, Stephanie B. Gaswirth
Paleozoic shale gas resources in the Sichuan Basin, China
The Sichuan Basin, China, is commonly considered to contain the world’s most abundant shale gas resources. Although its Paleozoic marine shales share many basic characteristics with successful United States gas shales, numerous geologic uncertainties exist, and Sichuan Basin shale gas production is nascent. Gas retention was likely compromised by the age of the shale reservoirs, multiple uplifts a
Authors
Christopher J. Potter