Publications
Publications from the staff of the Geology, Minerals, Energy, and Geophysics Science Center
Filter Total Items: 2477
Volcanism and tectonics of young basaltic fields in the eastern California shear zone, California, USA Volcanism and tectonics of young basaltic fields in the eastern California shear zone, California, USA
Circa 12 Ma, there was a fundamental reorganization of magmatism and tectonics in the Mojave Desert, California, USA, from basaltic to rhyolitic fields associated with extensional tectonics to dispersed basaltic monogenetic fields associated with the northwest- or east-striking strike-slip faults. The broad zone of strike-slip faults associated with the San Andreas transform margin...
Authors
David C. Buesch, David M. Miller
New U-Pb geochronology and geochemistry of Paleozoic metaigneous rocks from western Yukon and eastern Alaska, cross-border synthesis, and implications for tectonic models New U-Pb geochronology and geochemistry of Paleozoic metaigneous rocks from western Yukon and eastern Alaska, cross-border synthesis, and implications for tectonic models
The tectonic evolution of and relation between the Yukon-Tanana terrane and the Lake George assemblage, as well as other associated tectonic assemblages in western Yukon and eastern Alaska, have been debated for decades. The Yukon-Tanana terrane is widely considered to be an allochthonous rifted fragment derived from the Laurentian continental margin, whereas the Lake George assemblage...
Authors
Cynthia Dusel-Bacon, James K. Mortensen
Field evidence and indicators of rockfall fragmentation and implications for mobility Field evidence and indicators of rockfall fragmentation and implications for mobility
Rockfall fragmentation can play an important role in hazard studies and the design of protective measures. However, the current lack of modeling tools that incorporate rock fragmentation mechanics is a limitation to enhancing studies and design. This research investigates the fragmentation patterns of rockfalls and analyzes the resulting distribution of fragment sizes within...
Authors
Camilla Lanfranconi, Paolo Frattini, Federico Agliardi, Greg M. Stock, Brian D. Collins, Giovanni Crosta
Bayesian approaches to proxy uncertainty quantification in paleoecology: A mathematical justification and practical integration Bayesian approaches to proxy uncertainty quantification in paleoecology: A mathematical justification and practical integration
Paleoenvironmental data are essential for reconstructing environmental conditions in the distant past, and these reconstructions strongly depend on proxies and age–depth models. Proxies are indirect measurements that substitute for variables that cannot be directly measured, such as past precipitation. Conversely, an age–depth model is a tool that correlates the observed proxy with a...
Authors
Marco A. Aquino-Lopez, Lysanna Anderson, Joan-Albert Sanchez-Cabeza, Ana Carolina Ruiz-Fernandez, J. Andres Christen
Bedrock geologic map of Organ Pipe Cactus National Monument and vicinity, southwest Arizona Bedrock geologic map of Organ Pipe Cactus National Monument and vicinity, southwest Arizona
No abstract available.
Authors
Lisa A. Thompson, Gordon B. Haxel, Donald W. Peterson, Daniel J. May, Richard M. Tosdal, Robert J. Miller, Floyd Gray, Richard A. LeVeque, Paul J. Umhoefer
Subduction zone geometry modulates the megathrust earthquake cycle: Magnitude, recurrence, and variability Subduction zone geometry modulates the megathrust earthquake cycle: Magnitude, recurrence, and variability
Megathrust geometric properties exhibit some of the strongest correlations with maximum earthquake magnitude in global surveys of large subduction zone earthquakes, but the mechanisms through which fault geometry influences subduction earthquake cycle dynamics remain unresolved. Here, we develop 39 models of sequences of earthquakes and aseismic slip (SEAS) on variably-dipping planar and...
Authors
James Burkhardt Biemiller, Alice-Agnes Gabriel, Dave May, Lydia M. Staisch
Aurora: An open-source Python implementation of the EMTF package for magnetotelluric data processing using MTH5 and mt-metadata Aurora: An open-source Python implementation of the EMTF package for magnetotelluric data processing using MTH5 and mt-metadata
The Aurora software package robustly estimates single station and remote reference electromagnetic transfer functions (TFs) from magnetotelluric (MT) time series. Aurora is part of an open-source processing workflow that leverages the self-describing data container MTH5, which in turn leverages the general mt-metadata framework to manage metadata. These pre-existing packages simplify the
Authors
Karl Kappler, Jared R. Peacock, Gary D. Egbert, Andrew Frassetto, Lindsey Heagy, Anna Kelbert, Laura Keyson, Douglas W. Oldenburg, Timothy Ronan, Justin Sweet
Assessing potential effects of oil and gas development activities on groundwater quality near and overlying the Elk Hills and North Coles Levee Oil Fields, San Joaquin Valley, California Assessing potential effects of oil and gas development activities on groundwater quality near and overlying the Elk Hills and North Coles Levee Oil Fields, San Joaquin Valley, California
Groundwater resources are utilized near areas of intensive oil and gas development in California’s San Joaquin Valley. In this study, we examined chemical and isotopic data to assess if thermogenic gas or saline water from oil producing formations have mixed with groundwater near the Elk Hills and North Coles Levee Oil Fields in the southwestern San Joaquin Valley. Major ion...
Authors
John G. Warden, Matthew K. Landon, Michael J. Stephens, Tracy Davis, Janice M. Gillespie, Peter B. McMahon, Justin T. Kulongoski, Andrew G. Hunt, David H. Shimabukuro, Riley Gannon, Lyndsay B. Ball
Geochemistry of Archean komatiitic greenstone terranes of the Wyoming Province: Implications for geodynamic setting and mineralization Geochemistry of Archean komatiitic greenstone terranes of the Wyoming Province: Implications for geodynamic setting and mineralization
No abstract available.
Authors
Lisa Joanne Zieman, Jacob Evan Poletti, Michael Jenkins
A multi-methodological approach: Combining textural observations and geochronology to study the J-M Reef Package and its Hanging Wall, Stillwater Complex, Montana A multi-methodological approach: Combining textural observations and geochronology to study the J-M Reef Package and its Hanging Wall, Stillwater Complex, Montana
No abstract available.
Authors
Michael Jenkins, Sam R. Corson, Ennis Geraghty, S.L. Kamo, Heather A. Lowers, James E. Mungall
A Bayesian age from dispersed plagioclase and zircon dates in the Los Chocoyos ash, Central America A Bayesian age from dispersed plagioclase and zircon dates in the Los Chocoyos ash, Central America
The eruption that produced the modern Atitlán caldera in Guatemala has a Volcanic Explosivity Index (VEI) greater than 8, making it the largest of the Quaternary in the Central American Volcanic Arc (CAVA). It generated ∼1220 km3 (730 km3 dense rock equivalent) of dispersed rhyolitic ash and unwelded pyroclastic flow deposits known as the Los Chocoyos ash. Despite its scale, the age of...
Authors
Alec Baudry, Bradley S. Singer, Brian Jicha, Christine E. Jilly-Rehak, Jorge A. Vazquez, C. Brenhin Keller
Controls on stable methane isotope signatures in northern peatlands and potential shifts in signatures under permafrost thaw scenarios Controls on stable methane isotope signatures in northern peatlands and potential shifts in signatures under permafrost thaw scenarios
Northern peatlands are a globally significant source of methane (CH4), and emissions are projected to increase due to warming and permafrost loss. Understanding the microbial mechanisms behind patterns in CH4 production in these systems will be key to predicting annual emissions changes, with stable carbon isotopes (δ13C-CH4) being a powerful tool for characterizing these drivers. Given...
Authors
McKenzie A. Kuhn, Ruth K. Varner, Carmody K. McCalley, Clarice R. Perryman, Mika Aurela, Sophia A. Burke, Jeffrey Chanton, Patrick Crill, Jessica DelGreco, Jia Deng, Liam Heffernan, Christina Herrick, Suzanne B. Hodgkins, Cheristy P. Jones, Sari Juutinen, Evan S. Kane, Louis J. Lamit, Tuula Larmola, Erik Lilleskov, David Olefeldt, Michael W. Palace, Virginia I. Rich, Christopher Schulze, Joanne H. Shorter, Franklin Sullivan, Oliver Sonnentag, Merritt R. Turetsky, Mark Waldrop