Publications
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Luminescence ages and new interpretations of the timing and deposition of Quaternary sediments at Natural Trap Cave, Wyoming
Natural Trap Cave, located in the Big Horn Mountains of north-central Wyoming, has a history of trapping and preserving a range of North American fauna that plummeted into the deep vertical entrance. These animal remains were buried and preserved within sediments of the main chamber and, in turn, have helped elucidate the procession of faunal dynamics during the latest glacial cycle. The...
Authors
Shannon A. Mahan, John R. Wood, Dave M Lovelace, Juan Laden, Jenny McGuire, Julie Meachen
State of stress in areas of active unconventional oil and gas development in North America
In this paper, we present comprehensive data on stress orientation and relative magnitude in areas throughout North America where unconventional oil and gas are currently being developed. We find excellent agreement between maximum horizontal principal stress (SHmax) orientations over a wide range of depths, using multiple methods. In all basins studied, we observed coherent stress...
Authors
Jens-Erik Lundstern, Mark D. Zoback
Multi-species, multi-country analysis reveals North Americans are willing to pay for transborder migratory species conservation
Migratory species often provide ecosystem service benefits to people in one country while receiving habitat support in other countries. The multinational cooperation that could help ensure continued provisioning of these benefits by migration may be informed by understanding the economic values people in different countries place on the benefits they derive from migratory wildlife.We...
Authors
Wayne E. Thogmartin, Michelle A. Haefele, James Diffendorfer, Darius J. Semmens, Jonathan J. Derbridge, Aaron M. Lien, Ta-Ken Huang, Laura López-Hoffman
The global environmental agenda urgently needs a semantic web of knowledge
Progress in key social-ecological challenges of the global environmental agenda (e.g., climate change, biodiversity conservation, Sustainable Development Goals) is hampered by a lack of integration and synthesis of existing scientific evidence. Facing a fast-increasing volume of data, information remains compartmentalized to pre-defined scales and fields, rarely building its way up to...
Authors
Stefano Balbi, Kenneth J. Bagstad, Ainhoa Magrach, Maria Jose Sanz, Naikoa Aguilar-Amuchastegui, Carlo Guipponi, Ferdinando Villa
Oxygen isotopes of land snail shells in high latitude regions
The present study investigates the environmental significance of the oxygen isotopic composition of several modern land snail species collected along two north-to-south transects in Alaska and Scandinavia at latitudes between 60 and 70 °N. We tested the hypothesis that land snail shell δ18O values primarily track precipitation δ18O. The results show that shell δ18O values from...
Authors
Catherine B. Nield, Yurena Yanes, Jeffrey S. Pigati, Jason A. Rech, Ted von Proschwitz, Jeffrey C. Nekola
Photomosaics and logs associated with study of West Napa Fault at Ehlers Lane, north of Saint Helena, California
The West Napa Fault has previously been mapped as extending ~45 kilometers (km) from northern Vallejo to southern Saint Helena, California, dominantly running along the western edge of Napa Valley. A zone of fault strands (some previously unmapped) along a ~15-km section of the fault ruptured during the 2014 magnitude 6.0 South Napa earthquake, illustrating the need for further...
Authors
Belle E. Philibosian, Robert R. Sickler, Carol S. Prentice, Alexandra J. Pickering, Patrick Gannon, Kiara N. Broudy, Shannon A. Mahan, Jazmine N. Titular, Eli A. Turner, Cameron Folmar, Sierra F. Patterson, Emilie E. Bowman
Major reorganization of the Snake River modulated by passage of the Yellowstone Hotspot
The details and mechanisms for Neogene river reorganization in the U.S. Pacific Northwest and northern Rocky Mountains have been debated for over a century with key implications for how tectonic and volcanic systems modulate topographic development. To evaluate paleo-drainage networks, we produced an expansive data set and provenance analysis of detrital zircon U-Pb ages from Miocene to...
Authors
Lydia M. Staisch, James E. O'Connor, Charles M. Cannon, Christopher S. Holm-Denoma, Paul T. Link, John P. Lasher, Jeremy A. Alexander
Response to comment on “Evidence of humans in North America during the Last Glacial Maximum”
Madsen et al. question the reliability of calibrated radiocarbon ages associated with human footprints discovered recently in White Sands National Park, New Mexico, USA. On the basis of the geologic, hydrologic, stratigraphic, and chronologic evidence, we maintain that the ages are robust and conclude that the footprints date to between ~23,000 and 21,000 years ago.Madsen et al. (1)...
Authors
Jeffrey S. Pigati, Kathleen B. Springer, Matthew R. Bennett, David Bustos, Thomas. M. Urban, Vance T. Holliday, Sally C. Reynolds, Daniel Odess
From crystals to crustal-scale seismic anisotropy: Bridging the gap between rocks and seismic studies with digital geologic map data in Colorado
Deep continental crustal structures are enigmatic due to lack of direct exposures and limited tools to investigate them remotely. Seismic waves can sample these rocks, but most seismic methods focus on coarse crustal structures while laboratory measurements concentrate on crystal-scale rock properties, and little work has been conducted to bridge this interpretation gap. In some places...
Authors
Michael G. Frothingham, Kevin H. Mahan, Vera Schulte-Pelkum, Jonathan Caine, Frederick W. Vollmer
Mesilla / Conejos-Médanos Basin: U.S.-Mexico transboundary water resources and research needs
Synthesizing binational data to characterize shared water resources is critical to informing binational management. This work uses binational hydrogeology and water resource data in the Mesilla/Conejos-Médanos Basin (Basin) to describe the hydrologic conceptual model and identify potential research that could help inform sustainable management. The Basin aquifer is primarily composed of...
Authors
Andrew J. Robertson, Anne Marie Matherne, Jeff D. Pepin, Andre Ritchie, Donald S. Sweetkind, Andrew Teeple, Alfredo Granados Olivas, Ana Cristina García Vásquez, Kenneth C. Carroll, Erek H. Fuchs, Amy E. Galanter
Coastal paleogeography of the Pacific Northwest, USA, for the last 12,000 years accounting for three-dimensional earth structure
Predictive modeling of submerged archaeological sites requires accurate sea-level predictions in order to reconstruct coastal paleogeography and associated geographic features that may have influenced the locations of occupation sites such as rivers and embayments. Earlier reconstructions of the paleogeography of parts of the western U.S. coast used an assumption of eustatic sea level...
Authors
Jorie Clark, Jay R. Alder, Marisa Borreggine, Jerry X. Mitrovica, Konstantin Latychev
Evolution and taxonomy of the Paleogene calcareous nannofossil genus Hornibrookina
The genus Hornibrookina consists of enigmatic calcareous nannofossils that first appeared shortly after the K-Pg mass extinction. Due to their relative paucity in most published sections, specimens of this genus have not been previously studied in detail and their paleobiogeographic preferences and evolutionary history have been poorly understood. Biostratigraphic and morphometric...
Authors
Jean Self-Trail, David K. Watkins, James J. Pospichal, Ellen Seefelt