Publications
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A Bayesian nonparametric approach to unmixing detrital geochronologic data
Sedimentary deposits constitute the primary record of changing environmental conditions that have acted on Earth’s surface over geologic time. Clastic material is eroded from source locations (parents) in sediment routing systems and deposited at sink locations (children). Both parents and children have characteristics that vary across many different dimensions, including grain size, chemical comp
Authors
John R. Tipton, Glenn R. Sharman, Samuel Johnstone
Detrital zircon record of magmatism and sediment dispersal across the North American Cordilleran arc system (28-48°N)
As zircon U-Pb geochronology has become a leading method in sediment provenance studies and basin analysis over the past 20 years, the volume of detrital zircon data made available in published literature has enabled researchers to go beyond source-to-sink provenance studies to explore increasingly complex geologic problems. In this review, we utilize the growing body of detrital zircon data acqui
Authors
Theresa Maude Schwartz, Kathleen D. Surpless, Joseph Colgan, Samuel Johnstone, Christopher Holm-Denoma
Insights on geochemical, isotopic, and volumetric compositions of produced water from hydraulically fractured Williston Basin oil wells
Tracing produced water origins from wells hydraulically fractured with freshwater-based fluids is sometimes predicated on assumptions that (1) each geological formation contains compositionally unique brine and (2) produced water from recently hydraulically fractured wells resembles fresher meteoric water more so than produced water from older wells. These assumptions are not valid in Williston Ba
Authors
Tanya J. Gallegos, Colin A. Doolan, Rodney R. Caldwell, Mark A Engle, Matthew S. Varonka, Justin E. Birdwell, Glenn D. Jolly, Tyler B. Coplen, Thomas A. Oliver
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Identifying elusive piercing points along the North American transform margin using mixture modeling of detrital zircon data from sedimentary units and their crystalline sources
The San Gabriel and Canton faults represent early stages in the development of the San Andreas fault system. However, questions of timing of initiation and magnitude of slip on these structures remain unresolved, with published estimates ranging from 42-75 km and likely starting in the Miocene. This uncertainty in slip history reflects an absence of appropriate piercing points. We attempt to bette
Authors
Clark Gilbert, Zane R. Jobe, Samuel Johnstone, Glenn R. Sharman
Long-term African dust delivery to the eastern Atlantic Ocean from the Sahara and Sahel regions: Evidence from Quaternary paleosols on the Canary Islands, Spain
Africa is the most important source of dust in the world today and dust storms from that continent frequently deposit sediment on the nearby Canary Islands. Many investigators have inferred African dust inputs to Canary Islands paleosols based only on the presence of quartz. However, some local rocks do contain this mineral, so quartz alone is insufficient proof of dust deposition. Further, it is
Authors
Daniel R. Muhs, Joaquín Meco, James R. Budahn, Gary L. Skipp, Kathleen R. Simmons, Mathew C. Baddock, J.T. Betancort, A. Lomoschitz
When hazard avoidance is not an option: Lessons learned from monitoring the postdisaster Oso landslide, USA
On 22 March 2014, a massive, catastrophic landslide occurred near Oso, Washington, USA, sweeping more than 1 km across the adjacent valley flats and killing 43 people. For the following 5 weeks, hundreds of workers engaged in an exhaustive search, rescue, and recovery effort directly in the landslide runout path. These workers could not avoid the risks posed by additional large-scale slope collaps
Authors
Mark E. Reid, Jonathan W. Godt, Richard G LaHusen, Stephen L Slaughter, Thomas C. Badger, Brian D. Collins, William Schulz, Rex L. Baum, Jeffrey A. Coe, Edwin L Harp, Kevin M. Schmidt, Richard M. Iverson, Joel B. Smith, Ralph Haugerud, David L. George
The marine terraces of Santa Cruz Island, California: Implications for glacial isostatic adjustment models of last-interglacial sea-level history
Glacial isostatic adjustment (GIA) models hypothesize that along coastal California, last interglacial (LIG, broadly from ~130 to ~115 ka) sea level could have been as high as +11 m to +13 m, relative to present, substantially higher than the commonly estimated elevation of +6 m. Areas with low uplift rates can test whether such models are valid. Marine terraces on Santa Cruz Island have previousl
Authors
Daniel R. Muhs, R. Randall Schumann, Lindsey T. Groves, Kathleen R. Simmons, Christopher R. Florian
Detecting subtle change from dense landsat time series: Case studies of mountain pine beetle and spruce beetle disturbance
In contrast to abrupt changes caused by land cover conversion, subtle changes driven by a shift in the condition, structure, or other biological attributes of land often lead to minimal and slower alterations of the terrestrial surface. Accurate mapping and monitoring of subtle change are crucial for an early warning of long-term gradual change that may eventually result in land cover conversion.
Authors
Su Ye, John Rogan, Zhe Zhu, Todd Hawbaker, Sarah J. Hart, Robert A. Andrus, Arjan J.H. Meddens, Jeffery A. Hicke, J. Ronald Eastman, Dominik Kulakowski
Evidence for variable precipitation and discharge from Upper Cretaceous–Paleogene fluvial deposits of the Raton Basin, Colorado–New Mexico, U.S.A.
The Raton Basin of Colorado–New Mexico, USA, is the southeasternmost basin of the Laramide intraforeland province of North America. It hosts a thick succession (4.5 km or 15,000 ft) of Upper Cretaceous to Paleogene marine and continental strata that were deposited in response to the final regression of the Western Interior Seaway and the onset of Laramide intraforeland deformation. The Upper Creta
Authors
Theresa Maude Schwartz, Marieke Dechesne, Kristine L. Zellman
Demographic and potential biological removal models identify raptor species sensitive to current and future wind energy
A central challenge in applied ecology is understanding the effect of anthropogenic fatalities on wildlife populations and predicting which populations may be particularly vulnerable and in greatest need of management attention. We used 3 approaches to investigate potential effects of fatalities from collisions with wind turbines on 14 raptor species for both current (106 GW) and anticipated futur
Authors
James E. Diffendorfer, Jessica C. Stanton, Julie A. Beston, Wayne E. Thogmartin, Scott R. Loss, Todd E. Katzner, Douglas H. Johnson, Richard A. Erickson, Matthew D. Merrill, Margo D. Corum
By
Ecosystems Mission Area, Energy Resources Program, Species Management Research Program, Forest and Rangeland Ecosystem Science Center, Geology, Energy & Minerals Science Center, Geosciences and Environmental Change Science Center, Northern Prairie Wildlife Research Center, Upper Midwest Environmental Sciences Center
Assessing the uncertainties in climatic estimates based on vegetation assemblages: Examples from modern vegetation assemblages in the American Southwest
Assemblages of fossil plant remains have been widely used to reconstruct past climatic conditions, usually through the application of methods that involve either finding vegetation analogues on the modern landscape (and using the modern associated climatic values as the basis for an estimate) or using the modern climatic ranges of individual taxa in an assemblage to determine the range of a given
Authors
Robert S. Thompson, Katherine H Anderson, Richard T. Pelltier, Laura E. Strickland, Sarah Shafer, Patrick J. Bartlein
Reconstructing paleohydrology in the northwest Great Basin since the last deglaciation using Paisley Caves fish remains (Oregon, U.S.A.)
The arid northwest Great Basin underwent substantial hydroclimate changes in the past 15,000 years, greatly affecting its desert ecosystems and prehistoric people. There are conflicting interpretations of the timing of hydrologic changes in this region, requiring more records to resolve the dominant climatic drivers. The Paisley Caves archaeological site, located near former pluvial Lake Chewaucan
Authors
Adam M. Hudson, Meaghan M Emery-Wetherell, Patrick M Lubinski, Virginia L. Butler, Deanna N Grimstead, Dennis L Jenkins