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Publications

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Insights into the emplacement of upper-crustal plutons and their relationship to large silicic calderas, from field relationships, geochronology, and zircon trace element geochemistry in the Stillwater – Clan Alpine caldera complex, western Nevada, USA

Geologic mapping, new U-Pb zircon ages, and new and published 40Ar/39Ar sanidine ages document the timing and extent of Oligocene magmatism in the southern Stillwater Range and Clan Alpine Mountains of western Nevada, where Miocene extension has exposed at least six nested silicic calderas and underlying granitic plutons to crustal depths locally ≥ 9 km. Both caldera-forming rhyolitic tuffs and un
Authors
Joseph Colgan, David John, Christopher D. Henry, Kathryn E. Watts

Vegetation response of a dry shrubland community to feral goat management on the island of Moloka‘i, Hawai‘i

The Hawaiian Islands are well known for their unique ecosystem assemblages that have a high proportion of endemic flora and fauna. However, since human colonization of this archipelago—starting with the arrival of Polynesian sailors approximately 1,200 years ago, and particularly following western contact in 1778—thousands of non-native species have been introduced to the Islands and many of these
Authors
James D. Jacobi, Jonathan D. Stock

Recreation economics to inform migratory species conservation: Case study of the northern pintail

Quantification of the economic value provided by migratory species can aid in targeting management efforts and funding to locations yielding the greatest benefits to society and species conservation. Here we illustrate a key step in this process by estimating hunting and birding values of the northern pintail (Anas acuta) within primary breeding and wintering habitats used during the species’ annu
Authors
Brady J. Mattsson, James A. Dubovsky, Wayne E. Thogmartin, Kenneth J. Bagstad, Joshua H. Goldstein, John B. Loomis, James E. Diffendorfer, Darius J. Semmens, Ruscena Wiederholt, Laura Lopez-Hoffman

Reply to the discussion of Pinter et al. on ‘Fluvial system response to late Pleistocene-Holocene sea-level change on Santa Rosa Island, Channel Islands National Park, California’ by Schumann et al. (2016)

We appreciate the thoughtful discussion offered by Pinter et al. (2017) because it gives us an opportunity to elucidate some of the main points of our study, address some apparent misinterpretations, and recapitulate one of our conclusions. Pinter et al.’s discussion emphasizes and reinforces some of the important concepts we presented but also raises questions regarding specific aspects of our st
Authors
R. Randall Schumann, Jeffrey S. Pigati

A paleomagnetic age estimate for the draining of ancient Lake Alamosa, San Luis Valley, south-central Colorado, U.S.A.

In September 2009, a 99.4-m (326-ft) deep well was drilled proximal to Great Sand Dunes National Park and Preserve to explore the history and subsurface geology of the San Luis Valley, Colorado. Of particular interest was deciphering the evolution of ancient Lake Alamosa, which filled much of the San Luis Valley in the Pliocene and Pleistocene. Thick intervals of massive clay, recovered at the wel
Authors
Joshua K. Davis, Mark R. Hudson, V. J. S. Grauch

Domestic cat

The familiar domestic cat is not native to southern California and is considered an invasive spe-cies by biologists and conservation organizations. When owners abandon their cats, wild or feral populations may arise, as they have in San Diego County. Cats’ pelage color, tail length, and hair thickness vary widely, given human fascination with breeding diverse phenotypes, but all have a typical fel
Authors
James E. Diffendorfer

Late Quaternary fluvial history of Santa Cruz Island, California, USA

The geologic history of fluvial systems on Santa Cruz Island (SCI) is complex, involving responses to both allogenic and autogenic forcings. During periods of low or lowering sea level, canyons on the island were eroded and sediment was transported off the island onto the exposed marine shelf. When sea level rose, streams aggraded, building a sedimentary wedge that progressed from the shelf upstre
Authors
R. Randall Schumann, Jeffrey S. Pigati

Broken bones and hammerstones at the Cerutti Mastodon site: A reply to Haynes

Haynes [2017 “The Cerutti Mastodon.” PaleoAmerica 3 (3): 196–199] criticizes numerous aspects of our analysis of the Cerutti Mastodon (CM) site, but central among his points is the claim that heavy equipment broke the bones and stones that we interpret as evidence of ancient human activity. This notion can be discounted primarily because most of the relevant CM fragments were found coated in thick
Authors
Steven R. Holen, Thomas A. Deméré, Daniel C. Fisher, Richard Fullagar, James B. Paces, George T. Jefferson, Jared M. Beeton, Adam N. Rountrey, Kathleen A. Holen

Late Quaternary uplift along the North America-Caribbean plate boundary: Evidence from the sea level record of Guantanamo Bay, Cuba

The tectonic setting of the North America-Caribbean plate boundary has been studied intensively, but some aspects are still poorly understood, particularly along the Oriente fault zone. Guantanamo Bay, southern Cuba, is considered to be on a coastline that is under a transpressive tectonic regime along this zone, and is hypothesized to have a low uplift rate. We tested this by studying emergent re
Authors
Daniel R. Muhs, Eugene S. Schweig, Kathleen Simmons, Robert B. Halley

Understanding recurrent land use processes and long-term transitions in the dynamic south-central United States, c. 1800 to 2006

Forests have historically been under significant land use pressures that cause periods of degradation, clearance, and recovery. To understand these changes, studies are needed that place trends in a historical landscape context and also examine recent dynamics. Here, we use historical investigation (c. 1800) and an examination of land use and land cover change between 1973 and 2006 to establish a
Authors
Mark A. Drummond, Glenn E. Griffith, Roger F. Auch, Michael P. Stier, Janis L. Taylor, D. J. Hester, Jodi L. Riegle, Jamie L. McBeth

Taphonomic problems in reconstructing sea-level history from the late Quaternary marine terraces of Barbados

Although uranium series (U-series) ages of growth-position fossil corals are important to Quaternary sea-level history, coral clast reworking from storms can yield ages on a terrace dating to more than one high-sea stand, confounding interpretations of sea-level history. On northern Barbados, U-series ages corals from a thick storm deposit are not always younger with successively higher stratigrap
Authors
Daniel R. Muhs, Kathleen R. Simmons

Quantitative tools for implementing the new definition of significant portion of the range in the U.S. Endangered Species Act

In 2014, the Fish and Wildlife Service (FWS) and National Marine Fisheries Service announced a new policy interpretation for the U.S. Endangered Species Act (ESA). According to the act, a species must be listed as threatened or endangered if it is determined to be threatened or endangered in a significant portion of its range (SPR). The 2014 policy seeks to provide consistency by establishing that
Authors
Julia E. Earl, Samuel Nicol, Ruscena Wiederholt, Jay E. Diffendorfer, Darius J. Semmens, D. T. Tyler Flockhart, Brady Mattsson, Gary McCracken, D. Ryan Norris, Wayne E. Thogmartin, Laura Lopez-Hoffman