Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2354
Geologic field photograph map of the Grand Canyon region, 1967–2010
The Grand Canyon geologic field photograph collection contains 1,211 geotagged photographs collected during 43 years of geologic mapping from 1967 to 2010. The photographs document some key geologic features, structures, and rock unit relations that were used to compile nine geologic maps of the Grand Canyon region published at 1:100,000 scale, and many more maps published at 1:24,000 scale. Metad
Authors
George H. Billingsley, Gregory Goodwin, Sarah E. Nagorsen, Monica E. Erdman, Jason T. Sherba
A new set of basaltic tephras from southeastern Alaska represent key stratigraphic markers for the late Pleistocene
An 8-cm-thick black basaltic tephra with nine discrete normally graded beds is present in cores from a lake on Baker Island in southeastern Alaska. The estimated age of the tephra is 13,492 ± 237 cal yr BP. Although similar in age to the MEd tephra from the adjacent Mt. Edgecumbe Volcanic Field, this tephra is geochemically distinct. Black basaltic tephras recovered from two additional sites in so
Authors
Paul S. Wilcox, Jason A. Addison, Sarah J. Fowell, James F. Baichtal, Ken Severin, Daniel H. Mann
Geese mediate vegetation state changes with parallel effects on N cycling that leave nutritional legacies for offspring
Along the coastal fringe of the Yukon–Kuskokwim River Delta in southwestern Alaska, geese maintain grazing lawns dominated by a rhizomatous sedge that, when ungrazed, transitions to a taller, less palatable growth form that is taxonomically described as a different species. Nutrients recycled in goose feces, in conjunction with grazing, are critical to the rapid, nutritious growth of grazing lawns
Authors
Roger W. Ruess, Jack McFarland, Brian T. Person, James S. Sedinger
Controls on eolian landscape evolution in fractured bedrock
Wind abrasion is important for planetary landscape evolution, and wind‐abraded bedrock landscapes contain many landforms that are difficult to interpret. Here we exploit a natural experiment in Chile where topographic shielding by an upwind lava flow yields diverse erosional landforms in a downwind ignimbrite. Using a 3‐D topographic wind model, we find that low velocities in the wake of a lava lo
Authors
Jonathan P. Perkins, Noah J. Finnegan, Shanaka L. de Silva, Michael J. Willis
Insights into post-Miocene uplift of the western margin of the Colorado Plateau from the stratigraphic record of the lower Colorado River
The spatial and temporal distribution of Pliocene to Holocene Colorado River deposits (southwestern USA and northwestern Mexico) form a primary data set that records the evolution of a continental-scale river system and helps to delineate and quantify the magnitude of regional deformation. We focus in particular on the age and distribution of ancestral Colorado River deposits from field observatio
Authors
Ryan S. Crow, Keith A. Howard, L. Sue Beard, Phil Pearthree, Kyle House, Karl Karlstrom, Lisa Peters, William C. McIntosh, Colleen Cassidy, Tracey J. Felger, Debra Block
Detrital zircon geochronology along a structural transect across the Kahiltna assemblage in the western Alaska Range: Implications for emplacement of the Alexander-Wrangellia-Peninsular terrane against North America
The Kahiltna assemblage in the western Alaska Range consists of deformed Upper Jurassic and Cretaceous clastic strata that lie between the Alexander-Wrangellia-Peninsular (AWP) terrane to the south, and the Farewell and other peri-cratonic terranes to the north. Differences in detrital zircon populations and sandstone petrography allow geographic separation of the strata into two different success
Authors
Stephen E. Box, Susan M. Karl, James V. Jones, Dwight Bradley, Peter J. Haeussler, Paul B. O'Sullivan
Large loss of CO2 in winter observed across pan-arctic permafrost region
Recent warming in the Arctic, which has been amplified during the winter1,2,3, greatly enhances microbial decomposition of soil organic matter and subsequent release of carbon dioxide (CO2)4. However, the amount of CO2 released in winter is not known and has not been well represented by ecosystem models or empirically based estimates5,6. Here we synthesize regional in situ observations of CO2 flux
Authors
Susan M Natali, Jennifer D. Watts, Stefano Potter, Brendan M. Rogers, Sarah M. Ludwig, Anne-Katrin Selbmann, Patrick F. Sullivan, Benjamin W. Abbott, Kyle A. Arndt, Leah Birch, Mats P. Bjorkman, Anthony Bloom, Gerardo Celis, Torben R. Christiensen, Casper T. Christiansen, Roisin Commane, Elisabeth J. Cooper, Patrick Crill, Claudia Czimczik, Sergey Davydov, Jinyang Du, Jocelyn E. Egan, Bo Elberling, Eugenie S. Euskirchen, Thomas Friborg, Helene Genet, Mathias Gockede, Jordan P. Goodrich, Paul Grogan, Manuel Helbig, Elchin E. Jafarov, Julie Jastrow, Aram A.M. Kalhori, Yongwon Kim, John S Kimball, Lars Kutzbach, Mark J. Lara, Klaus S. Larsen, Michael M Loranty, Magnus Lund, Massimo Lupascu, Nima Madani, Avni Malhorta, Jack McFarland, David A. McGuire, Anders Michelson, Christina Minions, Walter C. Oechel, David Olefeldt, Frans-Jan Parmentier, Norbert Pirk, Benjamin Poulter, William L. Quinton, Fereidoun Rezanezhad, David Risk, Torsten Sachs, Kevin Schaefer, Neils M. Schmidt, Edward A. Schuur, Philipp R. Semenchuk, Gaius Shaver, Oliver Sonnentag, Gregory Starr, Claire C. Treat, Mark P. Waldrop, Yihui Wang, Jeffrey Welker, Christian Wille, Xiaofeng Xu, Zhen Zhang, Qianlai Zhuang, Donatella Zona
Geology and assessment of undiscovered oil and gas resources of the East Greenland Rift Basins Province, 2008
In 2007 the U.S. Geological Survey (USGS) completed an assessment of undiscovered, technically recoverable oil and gas resources in the East Greenland Rift Basins Province of Northeast Greenland. The province was selected as the prototype for the U.S. Geological Survey Circum-Arctic Resource Appraisal (CARA). In collaboration with the Geological Survey of Denmark and Greenland (GEUS), the province
Authors
Donald L. Gautier
Geology of the Monte Blanco borate deposits, Furnace Creek Wash, Death Valley, California
The Monte Blanco borate deposits are located along the southern margin of Death Valley’s Furnace Creek Wash, south of Twenty Mule Team Canyon road in California. Topographic and geologic mapping by S. Muessig and F.M. Byers, Jr., in 1954 documented these deposits’ geologic settings, geometries, mineralogies, and chemical characteristics. They estimated borate resources at the time to be in excess
Authors
S.J. Muessig, W.M. Pennell, Jeffrey R. Knott, James P. Calzia
Can geologic factors be predictive for distinguishing between productive and non-productive geothermal wells?
Geologic data are examined to evaluate whether certain geologic characteristics occur in higher abundance or higher magnitude along production geothermal wells relative to non-productive wells. We perform 3D geologic mapping, 3D stress modeling, and fault-slip modeling to estimate fourteen different geologic factors that are hypothesized to control or correlate with well productivity. The geologic
Authors
Drew L. Siler, Erick Burns, James E Faulds
Discovering blind geothermal systems in the Great Basin Region: An integrated geologic and geophysical approach for establishing geothermal play fairways: All phases
Most geothermal resources in the Great Basin region of the western USA are blind, and thus the discovery of new commercial-grade systems requires synthesis of favorable characteristics for geothermal activity. The geothermal play fairway concept involves integration of multiple parameters indicative of geothermal activity to identify promising areas for new development. This project integrated mul
Authors
E. Faulds James, Nicholas H. Hinz, Mark Coolbaugh, Bridget Ayling, Jonathan M.G. Glen, Jason W. Craig, Emma McConnville, Drew L. Siler, John Queen, Jeff Witter, Christian Hardwick
Where’s the rock: Using convolutional neural networks to improve land cover classification
While machine learning techniques have been increasingly applied to land cover classification problems, these techniques have not focused on separating exposed bare rock from soil covered areas. Therefore, we built a convolutional neural network (CNN) to differentiate exposed bare rock (rock) from soil cover (other). We made a training dataset by mapping exposed rock at eight test sites across the
Authors
Helen Petlyak, Corina Cerovski-Darriau, Vadim Zaliva, Jonathan D. Stock