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Browse more than 65,000 articles authored by our scientists over the past 100+ year history of the USGS and refine search by topic, location, year, and advanced search.

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Late Jurassic-Early Cretaceous orogenic gold mineralization in the Klamath Mountains, California: Constraints from 40Ar/39Ar dating of hydrothermal muscovite Late Jurassic-Early Cretaceous orogenic gold mineralization in the Klamath Mountains, California: Constraints from 40Ar/39Ar dating of hydrothermal muscovite

The Klamath Mountains gold province is the second most important historical producer in California, having produced more than 7 Moz of gold from both lode and placer sources. Hydrothermal muscovite grains from gold-bearing veins provide the first 40Ar/39Ar age constraints indicative of a protracted period of mineralization in the Klamath Mountains. The data indicate that the window for...
Authors
Ryan D. Taylor, Leah E. Morgan, Fred Jourdan, Thomas Monecke, Erin E. Marsh, Richard J. Goldfarb

20th-century strain accumulation on the Lesser Antilles megathrust based on coral microatolls 20th-century strain accumulation on the Lesser Antilles megathrust based on coral microatolls

The seismic potential of the Lesser Antilles megathrust remains poorly known, despite the potential hazard it poses to numerous island populations and its proximity to the Americas. As it has not produced any large earthquakes in the instrumental era, the megathrust is often assumed to be aseismic. However, historical records of great earthquakes in the 19th century and earlier, which...
Authors
Belle E. Philibosian, Nathalie Feuillet, Jennifer Weil-Accardo, Eric Jacques, Abel Guihou, Anne-Sophie Meriaux, Andre Anglade, Jean-Marie Saurel, Sebastien Deroussi

A call to record stormwater control functions and to share network data A call to record stormwater control functions and to share network data

Urban stormwater is an ongoing contributor to the degradation of the health of many watersheds and water bodies. In the United States, federal regulations (e.g., Clean Water Act) require monitoring and reporting of relevant water quality metrics in regulated waterbodies to ensure standards are being met, but decisions about how to manage urban stormwater are left up to state or other...
Authors
Benjamin Choat, Amber Pulido, Aditi S. Bhaskar, Rebecca Hale, Harry X. Zhang, Thomas Meixner, Lauren McPhillips, Kristina G. Hopkins, Jennifer Cherrier, Chingwen Cheng

A web-based tool for assessing the condition of benthic diatom assemblages in streams and rivers of the conterminous United States A web-based tool for assessing the condition of benthic diatom assemblages in streams and rivers of the conterminous United States

Benthic diatom assemblages are known to be indicative of water quality but have yet to be widely adopted in biological assessments in the United States due to several limitations. Our goal was to address some of these limitations by developing regional multi-metric indices (MMIs) that are robust to inter-laboratory taxonomic inconsistency, adjusted for natural covariates, and sensitive...
Authors
Daren M. Carlisle, Sarah A. Spaulding, Meredith Tyree, Nicholas O. Schulte, Sylvia S Lee, Richard M. Mitchell, Amina A. Pollard

Active‐source interferometry in marine and terrestrial environments: Importance of directionality and stationary phase Active‐source interferometry in marine and terrestrial environments: Importance of directionality and stationary phase

We utilize active‐source seismic interferometry with dense seismic arrays both offshore and onland to explore the utility of this method to create virtual sources and reveal body‐wave reflections in these two different environments. We first utilize data from an ocean‐bottom cable (OBC) array in the Gulf of Mexico with equal numbers of sources (160 airgun shots) and receivers (160 ocean...
Authors
Steven Plescia, Anne Sheehan, Seth S. Haines

Importance of nonindigenous harpacticoids (Crustacea: Copepoda) decrease with depth in Lake Ontario Importance of nonindigenous harpacticoids (Crustacea: Copepoda) decrease with depth in Lake Ontario

Harpacticoid copepods can be a substantial component of the meiobenthic community in lakes and serve an ecological role as detritivores. Here we present the first species-level lake-wide quantitative assessment of the harpacticoid assemblage of Lake Ontario with emphasis on the status of nonindigenous species. Additionally, we provide COI-5P sequences of harpacticoid taxa through Barcode...
Authors
Joe K. Connolly, Brian O’Malley, Patrick Hudson, James M. Watkins, Lyubov E. Burlakova, Lars G. Rudstam

Inter-nesting movements, migratory pathways, and resident foraging areas of green sea turtles (Chelonia mydas) satellite-tagged in Southwest Florida Inter-nesting movements, migratory pathways, and resident foraging areas of green sea turtles (Chelonia mydas) satellite-tagged in Southwest Florida

Globally, sea turtle research and conservation efforts are underway to identify important high-use areas where these imperiled individuals may be resident for weeks to months to years. In the southeastern Gulf of Mexico, recent telemetry studies highlighted post-nesting foraging sites for federally endangered green turtles (Chelonia mydas) around the Florida Keys. In order to delineate...
Authors
Kelly A Sloan, David S. Addison, Andrew T. Glinsky, Allison Benscoter, Kristen Hart

Extensive species diversification and marked geographic phylogenetic structure in the Mesoamerican genus Stenopelmatus (Orthoptera: Stenopelmatidae: Stenopelmatinae) revealed by mitochondrial and nuclear 3RAD data Extensive species diversification and marked geographic phylogenetic structure in the Mesoamerican genus Stenopelmatus (Orthoptera: Stenopelmatidae: Stenopelmatinae) revealed by mitochondrial and nuclear 3RAD data

The Jerusalem cricket subfamily Stenopelmatinae is distributed from south-western Canada through the western half of the United States to as far south as Ecuador. Recently, the generic classification of this subfamily was updated to contain two genera, the western North American Ammopelmatus, and the Mexican, and central and northern South American Stenopelmatus. The taxonomy of the...
Authors
Jorge S. Gutiérrez, Alejandro Zaldivar-Riveron, David B Weissman, Amy G. Vandergast

It’s complicated and it depends: A review of the effects of ecosystem changes on Walleye and Yellow Perch populations in North America It’s complicated and it depends: A review of the effects of ecosystem changes on Walleye and Yellow Perch populations in North America

Walleye Sander vitreus and Yellow Perch Perca flavescens are culturally, economically, and ecologically significant fish species in North America that are affected by drivers of global change. Here, we review and synthesize the published literature documenting the effects of ecosystem changes on Walleye and Yellow Perch. We focus on four drivers: climate (including temperature and...
Authors
Gretchen J.A. Hansen, Jenna Ruzich, Corey A. Krabbenhoft, Holly Kundel, Shad Mahlum, Christopher I. Rounds, Amanda O. Van Pelt, Lawrence D. Eslinger, Dale E. Logsdon, Daniel A. Isermann

Influence of anthropogenic subsidies on movements of common ravens Influence of anthropogenic subsidies on movements of common ravens

Anthropogenic subsidies can benefit populations of generalist predators such as common ravens (ravens; Corvus corax), which in turn may depress populations of many types of species at lower-trophic levels, including desert tortoises (Gopherus agassizii) or greater sage-grouse (Centrocercus urophasianus). Management of subsidized ravens often has targeted local breeding populations that...
Authors
Adam E. Duerr, Peter H. Bloom, Kerry Ross, Tricia A. Miller, Melissa A. Braham, Amy L Fesnock, Todd E. Katzner

Open-source resources help navigate new IM regulations Open-source resources help navigate new IM regulations

The revision of federal safety regulations for integrity management of gas transmission pipelines to require explicit consideration of seismicity increases the importance for operators to be actively identifying high-consequence areas (HCAs), evaluating seismic-related threats, and choosing a risk model to support risk management decisions. To ensure equal access to information by both...
Authors
N. Simon Kwong, Kishor S. Jaiswal, J. W. Baker, Nico Luco, K. A. Ludwig, Vasey J. Stephens

Watershed-scale risk to aquatic organisms from complex chemical mixtures in the Shenandoah River Watershed-scale risk to aquatic organisms from complex chemical mixtures in the Shenandoah River

River waters contain complex chemical mixtures derived from natural and anthropogenic sources. Aquatic organisms are exposed to the entire chemical composition of the water, resulting in potential effects at the organismal through ecosystem level. This study applied a holistic approach to assess landscape, hydrological, chemical, and biological variables. On-site mobile laboratory...
Authors
Larry B. Barber, Kaycee E. Faunce, David Bertolatus, Michelle L. Hladik, Jeramy Roland Jasmann, Steffanie H. Keefe, Dana W. Kolpin, Michael T. Meyer, Jennifer L. Rapp, David A. Roth, Alan M. Vajda
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