Publications
Filter Total Items: 824
Constraints on timing and rates of late Cenozoic incision by the Colorado River in Glenwood Canyon, Colorado: A preliminary synopsis
No abstract available.
Authors
Robert M. Kirkham, Michael J. Kunk, Bruce Bryant, Randall K. Streufert
Hydrogeologic setting and potential for denitrification in ground water, Coastal Plain of southern Maryland
The types and distribution of Coastal Plain sediments in the Patuxent River Basin may contribute to relatively low concentrations of nitrate (typically less than 1 milligram per liter) in stream base flow because of the chemical reduction of dissolved nitrate (denitrification) in ground water. Water chemistry data from synoptic stream base-flow surveys in the Patuxent River Basin show higher disso
Authors
David E. Krantz, David S. Powars
Climatic variability in the eastern United States over the past millennium from Chesapeake Bay sediments
Salinity oscillations caused by multidecadal climatic variability had major impacts on the Chesapeake Bay estuarine ecosystem during the past 1000 yr. Microfossils from sediments dated by radiometry (14C, 137Cs, 210Pb) and pollen stratigraphy indicate that salinity in mesohaline regions oscillated 10-15 ppt during periods of extreme drought (low fresh-water discharge) and wet climate (high dischar
Authors
Thomas M. Cronin, Debra A. Willard, A. Karlsen, S. Ishman, S. Verardo, John McGeehin, R. Kerhin, C. Holmes, S. Colman, A. Zimmerman
Digital airborne time domain electromagnetic data from surveys over Cochiti Pueblo, Rio Puerco, and Rio Rancho, New Mexico
The Albuquerque-Santa Fe region is rapidly growing. The Santa Fe Group aquifer in the Middle Rio Grande Basin (MRGB) is the main source of municipal water for the greater Albuquerque metropolitan area and is more limited than previously thought (Thorn et al., 1993). The MRGB, as defined hydrologically and used here, is the area within the Rio Grande Valley extending from Cochiti Dam downstream to
Authors
Maria Deszcz-Pan, B. D. Rodriguez, J. P. Doucette, Michel Godbout, J. M. Williams, D. A. Sawyer, B. D. Stone, V. J. Grauch
Digital geologic map of the Harpers Ferry National Historical Park
No abstract available.
Authors
Scott Southworth, D. K. Brezinski, Randall C. Orndorff, Kerry M. Lagueux, Peter G. Chirico
Isotopic ages from intrusive rocks near the Stuyahok gold placer deposits, south-central Holy Cross quadrangle, Alaska: A section in Geologic studies in Alaska by the U.S. Geological Survey, 1998
In the Stuyahok area of the south-central Holy Cross quadrangle, Alaska, felsic to intermediate dikes and sills intrude Lower Cretaceous volcanic and volcaniclastic rocks of the Koyukuk terrane. These previously undated intrusions are the probable source of at least 933 kg (30,000 oz) of past placer gold production. Additional placer, and perhaps lode, resources are likely present at Stuyahok. New
Authors
Marti L. Miller, Robert D. Tucker, Paul W. Layer, Thomas K. Bundtzen
Preliminary stratigraphic database for the subsurface Tertiary and uppermost Cretaceous sediments of Dorchester County, South Carolina
No abstract available.
Authors
Gregory Gohn, Laurel M. Bybell, Peter G. Chirico, R. A. Christopher, Lucy E. Edwards, N. O. Frederiksen, D. C. Prowell, Jean Self-Trail, Robert E. Weems
Neogene calcareous nannofossil biostratigraphy of the Caribbean coast of Panama and Costa Rica
No abstract available.
Authors
Laurel M. Bybell
The Central Great Lakes Geologic Mapping Coalition
The State Geological Surveys of Illinois, Indiana, Michigan, and Ohio joined with the U.S. Geological Survey (USGS, under the Earth Surface Dynamics Program) to form the Central Great Lakes Geologic Mapping Coalition. These four States have a similar geologic heritage and need to address common societal issues about land and water resources, the environment, and geologic hazards. By pooling their
Authors
Sustainable growth in America's heartland: 3-D geologic maps as the foundation
The Central Great Lakes States of Illinois, Indiana, Michigan, and Ohio constitute one of the most productive and economically important regions in the country—America’s heartland. The agriculture, industry, business, recreation, and ecology of these States are based on a common geologic heritage. During the last 1.8 million years, glaciers repeatedly advanced and retreated across the region, leav
Authors
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Historical trends in salinity and substrate in central and northern Florida Bay: A Paleoecological Reconstruction using modern analogue data
Understanding the natural spatial and temporal variability that exists within an ecosystem is a critical component of efforts to restore systems to their natural state. Analysis of benthic foraminifers and molluscs from modern monitoring sites within Florida Bay allows us to determine what environmental parameters control spatial and temporal variability of their assemblages. Faunal assemblages as
Authors
G. Lynn Wingard, Scott E. Ishman
Neoproterozoic(?) to Pennsylvanian inner-shelf, miogeoclinal strata in Sierra Agua Verde, Sonora, Mexico
No abstract available.
Authors
John H. Stewart, Forrest G. Poole, Anita G. Harris, John E. Repetski, Bruce R. Wardlaw, Bernard L. Mamet, J. M. Morales-Ramirez