Hydrothermal, biogenic, and seawater components in metalliferous black shales of the Brooks Range, Alaska: Synsedimentary metal enrichment in a carbonate ramp setting
John F. Slack, David Selby, Julie A. Dumoulin
2015, Economic Geology (110) 653-675
Trace element and Os isotope data for Lisburne Group metalliferous black shales of Middle Mississippian (early Chesterian) age in the Brooks Range of northern Alaska suggest that metals were sourced chiefly from local seawater (including biogenic detritus) but also from externally derived hydrothermal fluids. These black shales are interbedded with...
Having it both ways? Land use change in a U.S. midwestern agricultural ecoregion
Roger F. Auch, Chris R. Laingen
2015, Professional Geographer (67) 84-97
Urbanization has been directly linked to decreases in area of agricultural lands and, as such, has been considered a threat to food security. Although the area of land used to produce food has diminished, often overlooked have been changes in agricultural output. The Eastern Corn Belt Plains (ECBP) is an...
Cambrian–Ordovician of the central Appalachians:Correlations and event stratigraphy of carbonate platform andadjacent deep-water deposits
David K. Brezinski, John F. Taylor, John E. Repetski, James D. Loch
2015, Book chapter, Geological Society of America field guide
This trip seeks to illustrate the succession of Cambrian and Ordovician facies deposited within the Pennsylvania and Maryland portion of the Great American Carbonate Bank. From the Early Cambrian (Dyeran) through Late Ordovician (Turinan), the Laurentian paleocontinent was rimmed by an extensive carbonate platform. During this protracted period of time, a...
An ignimbrite caldera from the bottom up: Exhumed floor and fill of the resurgent Bonanza caldera, Southern Rocky Mountain volcanic field, Colorado
Peter W. Lipman, Matthew J. Zimmerer, William C. McIntosh
2015, Geosphere (11) 1902-1947
Among large ignimbrites, the Bonanza Tuff and its source caldera in the Southern Rocky Mountain volcanic field display diverse depositional and structural features that provide special insights concerning eruptive processes and caldera development. In contrast to the nested loci for successive ignimbrite eruptions at many large multicyclic calderas elsewhere, Bonanza...
Early Permian conodont fauna and stratigraphy of the Garden Valley Formation, Eureka County, Nevada
Bruce R. Wardlaw, Dora M. Gallegos, Valery V. Chernykh, Walter S. Snyder
2015, Micropaleontology (61) 369-387
The lower part of the Garden Valley Formation yields two distinct conodont faunas. One of late Asselian age dominated by Mesogondolella and Streptognathodus and one of Artinskian age dominated by Sweetognathus with Mesogondolella. The Asselian fauna contains the same species as those found in the type area of the Asselian...
Provenance and detrital zircon geochronologic evolution of lower Brookian foreland basin deposits of the western Brooks Range, Alaska, and implications for early Brookian tectonism
Thomas E. Moore, Paul B. O’Sullivan, Christopher J. Potter, Raymond A. Donelick
2015, Geosphere (11) 93-122
The Upper Jurassic and Lower Cretaceous part of the Brookian sequence of northern Alaska consists of syntectonic deposits shed from the north-directed, early Brookian orogenic belt. We employ sandstone petrography, detrital zircon U-Pb age analysis, and zircon fission-track double-dating methods to investigate these deposits in a succession of thin...
Denitrification in the Mississippi River network controlled by flow through river bedforms
Jesus D. Gomez-Velez, Judson W. Harvey, M. Bayani Cardenas, Brian Kiel
2015, Nature Geoscience (8) 941-945
Increasing nitrogen concentrations in the world’s major rivers have led to over-fertilization of sensitive downstream waters. Flow through channel bed and bank sediments acts to remove riverine nitrogen through microbe-mediated denitrification reactions. However, little is understood about where in the channel network this biophysical process is most efficient, why certain...
Eocene and Miocene extension, meteoric fluid infiltration, and core complex formation in the Great Basin (Raft River Mountains, Utah)
Katharina Methner, Andreas Mulch, Christian Teyssier, Michael L. Wells, Michael A. Cosca, Raphael Gottardi, Aude Gebelin, C. Page Chamberlain
2015, Tectonics (34) 680-693
Metamorphic core complexes (MCCs) in the North American Cordillera reflect the effects of lithospheric extension and contribute to crustal adjustments both during and after a protracted subduction history along the Pacific plate margin. While the Miocene-to-recent history of most MCCs in the Great Basin, including the Raft River-Albion-Grouse Creek MCC,...
River corridor science: Hydrologic exchange and ecological consequences from bedforms to basins
Judson Harvey, Michael Gooseff
2015, Water Resources Research (51) 6893-6922
Previously regarded as the passive drains of watersheds, over the past 50 years, rivers have progressively been recognized as being actively connected with off-channel environments. These connections prolong physical storage and enhance reactive processing to alter water chemistry and downstream transport of materials and energy. Here we propose river corridor...
Field trip guidebook for the post-meeting field trip: The Central Appalachians
John F. Taylor, James D. Loch, G. Robert Ganis, John E. Repetski, Charles E. Mitchell, Gale C. Blackmer, David K. Brezinski, Daniel Goldman, Randall C. Orndorff, Bryan K. Sell
2015, Stratigraphy (12) 297-413
The lower Paleozoic rocks to be examined on this trip through the central Appalachians represent an extreme range of depositional environments. The lithofacies we will examine range from pelagic radiolarian chert and interbedded mudstone that originated on the deep floor of the Iapetus Ocean, through mud cracked supratidal dolomitic laminites...
Ants of the national park of American Samoa
Paul C. Banko, Robert W. Peck
2015, Technical Report HCSU-061
American Samoa makes up the eastern end of the Samoan Archipelago. On the islands of Tutuila, Taʽū and Ofu, the National Park of American Samoa (NPSA) protects about 4,000 ha of coastal, mid-slope and ridge-top forest. While the ant fauna of the Samoan Archipelago is considered relatively well documented, much...
Flood trends: Not higher but more often
Robert M. Hirsch, Stacey A. Archfield
2015, Nature Climate Change (5) 198-199
Heavy precipitation has increased worldwide, but the effect of this on flood magnitude has been difficult to pinpoint. An alternative approach to analysing records shows that, in the central United States, floods have become more frequent but not larger....
Potential nitrogen critical loads for northern Great Plains grassland vegetation
Amy J. Symstad, Anine T. Smith, Wesley E. Newton, Alan K. Knapp
2015, Natural Resource Report NPS/NGPN/NRR - 2015/989
The National Park Service is concerned that increasing atmospheric nitrogen deposition caused by fossil fuel combustion and agricultural activities could adversely affect the northern Great Plains (NGP) ecosystems in its trust. The critical load concept facilitates communication between scientists and policy makers or land managers by translating the complex effects...
Ordovician of Germany Valley, West Virginia
John T. Haynes, Keith E. Goggin, Randall C. Orndorff, Lisa R. Goggin
2015, Stratigraphy (12) 1-45
This trip will consist of stops at five locations (Fig. 1) that provide a detailed look at the strata in a major part of the Ordovician section in Germany Valley, Pendleton County, West Virginia. At these stops, we will highlight a varied sequence of carbonate and siliciclastic strata that accumulated during the...
Estimating mean long-term hydrologic budget components for watersheds and counties: An application to the commonwealth of Virginia, USA
Ward E. Sanford, David L. Nelms, Jason P. Pope, David L. Selnick
2015, Hydrology: Current Research (6) 1-22
Mean long-term hydrologic budget components, such as recharge and base flow, are often difficult to estimate because they can vary substantially in space and time. Mean long-term fluxes were calculated in this study for precipitation, surface runoff, infiltration, total evapotranspiration (ET), riparian ET, recharge, base flow (or groundwater discharge) and...
A field comparison of multiple techniques to quantify groundwater - surface-water interactions
Ricardo Gonzalez-Pinzon, Adam S Ward, Christine E Hatch, Adam N. Wlostowski, Kamini Singha, Michael N. Gooseff, Roy Haggerty, Judson Harvey, Olaf A Cirpka, James T Brock
2015, Freshwater Science (34) 139-160
Groundwater–surface-water (GW-SW) interactions in streams are difficult to quantify because of heterogeneity in hydraulic and reactive processes across a range of spatial and temporal scales. The challenge of quantifying these interactions has led to the development of several techniques, from centimeter-scale probes to whole-system tracers, including chemical, thermal, and electrical...
Integrating climate change into northeast and midwest State Wildlife Action Plans
Michelle D. Staudinger, Toni L. Morelli, Alexander Bryan, editor(s)
2015, Report
The Department of Interior Northeast Climate Science Center (NE CSC) conducts research that responds to the regional natural resource management community’s needs to anticipate, monitor, and adapt to climate change. The NE CSC is supported by a consortium of partners that includes the University of Massachusetts Amherst, College of Menominee...
Paleoseismologic evidence for large-magnitude (Mw 7.5-8.0) earthquakes on the Ventura blind thrust fault: Implications for multifault ruptures in the Transverse Ranges of southern California
Lee J. McAuliffe, James F. Dolan, Edward J. Rhodes, Judith Hubbard, John H. Shaw, Thomas L. Pratt
2015, Geosphere (11) 1629-1650
Detailed analysis of continuously cored boreholes and cone penetrometer tests (CPTs), high-resolution seismic-reflection data, and luminescence and 14C dates from Holocene strata folded above the tip of the Ventura blind thrust fault constrain the ages and displacements of the two (or more) most recent earthquakes. These two earthquakes, which are...
Net ecosystem production and organic carbon balance of U.S. East Coast estuaries: A synthesis approach
Maria Herrmann, Raymond G. Najjar, W. Michael Kemp, Richard B. Alexander, Elizabeth W. Boyer, Wei-Jun Cai, Peter C. Griffith, Kevin D. Kroeger, S. Leigh McCallister, Richard A. Smith
2015, Global Biogeochemical Cycles (29) 96-111
Net ecosystem production (NEP) and the overall organic carbon budget for the estuaries along the East Coast of the United States are estimated. We focus on the open estuarine waters, excluding the fringing wetlands. We developed empirical models relating NEP to loading ratios of dissolved inorganic nitrogen to total organic...
Cenozoic stratigraphy and structure of the Chesapeake Bay region
David S. Powars, Lucy E. Edwards, Susan M. Kidwell, J. Stephen Schindler
2015, Book
The Salisbury embayment is a broad tectonic downwarp that is filled by generally seaward-thickening, wedge-shaped deposits of the central Atlantic Coastal Plain. Our two-day field trip will take us to the western side of this embayment from the Fall Zone in Washington, D.C., to some of the bluffs along Aquia...
Episodic deflation-inflation events at Kīlauea Volcano and implications for the shallow magma system
Kyle R. Anderson, Michael P. Poland, Jessica H. Johnson, Asta Miklius
Rebecca Carey, Valerie Cayol, Michael P. Poland, Dominique Weis, editor(s)
2015, Book chapter, Hawaiian volcanoes: From source to surface
Episodic variations in magma pressures and flow rates at Kīlauea Volcano, defined by a characteristic temporal evolution and termed deflation-inflation (DI) events, have been observed since at least the 1990s. DI events consist of transient, days-long deflations and subsequent reinflations of the summit region, accompanied since 2008 by fluctuations in...
The Yellowstone “hot spot” track results from migrating basin-range extension
Gillian R. Foulger, Robert L. Christiansen, Don L. Anderson
Gillian R. Foulger, Michele Lustrino, Scott D. King, editor(s)
2015, Book chapter, The interdisciplinary earth: A volume in honor of Don L. Anderson (GSA Special Papers volume 514)
Whether the volcanism of the Columbia River Plateau, eastern Snake River Plain, and Yellowstone (western U.S.) is related to a mantle plume or to plate tectonic processes is a long-standing controversy. There are many geological mismatches with the basic plume model as well as logical flaws, such as citing data...
Copper toxicity and organic matter: Resiliency of watersheds in the Duluth Complex, Minnesota, USA
Nadine M. Piatak, Robert R. Seal, Perry M. Jones, Laurel G. Woodruff
2015, Conference Paper, Proceedings of the 10th International Conference on Acid Rock Drainage and IMWA Annual Conference
We estimated copper (Cu) toxicity in surface water with high dissolved organic matter (DOM) for unmined mineralized watersheds of the Duluth Complex using the Biotic Ligand Model (BLM), which evaluates the effect of DOM, cation competition for biologic binding sites, and metal speciation. A sediment-based BLM was used to estimate...
Reaction modeling of drainage quality in the Duluth Complex, northern Minnesota, USA
Robert R. Seal, Kim Lapakko, Nadine M. Piatak, Laurel G. Woodruff
2015, Conference Paper
Reaction modeling can be a valuable tool in predicting the long-term behavior of waste material if representative rate constants can be derived from long-term leaching tests or other approaches. Reaction modeling using the REACT program of the Geochemist’s Workbench was conducted to evaluate long-term drainage quality affected by disseminated Cu-Ni-(Co-)-PGM...
REE enrichment in granite-derived regolith deposits of the southeast United States: Prospective source rocks and accumulation processes
Nora K. Foley, Robert A. Ayuso
G.J. Simandl, M. Neetz, editor(s)
2015, Conference Paper, Symposium on strategic and critical materials proceedings (British Columbia Geological Survey Paper 2015-3)
The Southeastern United States contains numerous anorogenic, or A-type, granites, which constitute promising source rocks for REE-enriched ion adsorption clay deposits due to their inherently high concentrations of REE. These granites have undergone a long history of chemical weathering, resulting in thick granite-derived regoliths, akin to those of South China,...
