Publications
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Assessment of undiscovered continuous oil and gas resources in the Upper Cretaceous Tuscaloosa marine shale of the U.S. Gulf Coast, 2018
Using a geology-based assessment methodology, the U.S. Geological Survey assessed mean undiscovered, technically recoverable continuousresources of 1.5 billion barrels of oil and 4.6 trillion cubic feet of gas in the Upper Cretaceous Tuscaloosa marine shale in onshore and State waters ofLouisiana, Mississippi, Alabama, and Florida in the U.S. Gulf Coast region.
Authors
Paul C. Hackley, Catherine B. Enomoto, Brett J. Valentine, William A. Rouse, Celeste D. Lohr, Frank T. Dulong, Javin J. Hatcherian, Sean T. Brennan, William H. Craddock, Thomas M. Finn, Stephanie B. Gaswirth, Phuong A. Le, Heidi M. Leathers-Miller, Kristen R. Marra, Tracey J. Mercier, Stanley T. Paxton, Katherine J. Whidden, Cheryl A. Woodall, Christopher J. Schenk
Gas emissions, tars, and secondary minerals at the Ruth Mullins and Tiptop coal mine fires
Both the Tiptop and Ruth Mullins coal fires, Kentucky, were reinvestigated in 2009 and 2010. The Tiptop fire was not as active in 2009 and may have been on the path to burning out at the time of the 2009 visit. The Ruth Mullins coal mine fire, Perry County, Kentucky, has been the subject of several field investigations, including November 2009–February 2010 investigations in which we measured gas
Authors
Jennifer M. K. O'Keefe, Erika R. Neace, Maxwell L. Hammond, James C. Hower, Mark A. Engle, Joseph A. East, Nicholas J. Geboy, Ricardo A. Olea, Kevin R. Henke, Gregory C. Copley, Edward W. Lemley, Rachel S. Hatch Nally, Antonia E. Hansen, Allison R. Richardson, Anne B. Satterwhite, Glenn B. Stracher, Larry F. Radke, Charles Smeltzer, Christopher Romanek, Donald R. Blake, Paul A. Schroeder, Stephen D. Emsbo-Mattingly, Scott A. Stout
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
Subseasonal variations in marine reservoir age from pre-bomb Donax obesulus and Protothaca asperrima shell carbonate
Two Donax obesulus and two Protothaca asperrima shells collected prior to the nuclear testing of the 1950's were micromilled at sub-seasonal resolution to yield new reservoir effect (ΔR) estimates for the coast of Peru. Shells from northern (4°40′S to 8°14′S) and central (13°52′S) Peru produced ΔR values of 123 ± 50 and 110 ± 49 years respectively. We found such values statistically indistinguisha
Authors
Miguel F. Etayo-Cadavid, C. Fred T. Andrus, Kevin B. Jones, Gregory W. L. Hodgins
Geoelectric hazard maps for the Pacific Northwest
Maps of extreme value, horizontal component geoelectric field amplitude are constructed for the Pacific Northwest United States (and parts of neighboring Canada). Multidecade long geoelectric field time series are calculated by convolving Earth surface impedance tensors from 71 discrete magnetotelluric survey sites across the region with historical 1‐min (2‐min Nyquist) geomagnetic variation time
Authors
Jeffrey J. Love, Greg M. Lucas, Anna Kelbert, Paul A. Bedrosian
Cadmium isotope fractionation during coal combustion: Insights from two U.S. coal-fired power plants
Coal combustion, one of the principal energy sources of electricity in the United States, produces over 100 million tons of coal combustion products (CCPs) per year in the U.S. The reuse and disposal of CCPs has the potential to release toxic trace elements, including cadmium (Cd), into the environment. In this study, we investigated CCPs, including bottom ash (BA), economizer fly ash (EFA), and f
Authors
Fotio Fouskas, Ma Lin, Mark A. Engle, Leslie F. Ruppert, Nicholas J. Geboy, Matthew A. Costa
Outburst floods provide erodability estimates consistent with long-term landscape evolution
Most current models for the landscape evolution over geological timescales are based on semi-empirical laws that consider riverbed incision proportional to rock erodability (dependent on lithology) and to the work performed by water flow (stream power). However, the erodability values obtained from these models are entangled with poorly known conditions of past climate and streamflow. Here we use
Authors
Daniel Garcia-Castellanos, Jim E. O'Connor
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