Publications
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The Eocene-Oligocene sedimentary record in the Chesapeake Bay impact structure: Implications for climate and sea-level changes on the western Atlantic margin The Eocene-Oligocene sedimentary record in the Chesapeake Bay impact structure: Implications for climate and sea-level changes on the western Atlantic margin
A multidisciplinary investigation of the Eocene-Oligocene transition in the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville core from the Chesapeake Bay impact basin was conducted in order to document environmental changes and sequence stratigraphic setting. Planktonic foraminifera and calcareous nannofossil biostratigraphy indicate...
Authors
P. Schulte, B.S. Wade, A. Kontny, Jean Self-Trail
Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth Geologic columns for the ICDP-USGS Eyreville A and C cores, Chesapeake Bay impact structure: Postimpact sediments, 444 to 0 m depth
A 443.9-m-thick, virtually undisturbed section of postimpact deposits in the Chesapeake Bay impact structure was recovered in the Eyreville A and C cores, Northampton County, Virginia, within the "moat" of the structure's central crater. Recovered sediments are mainly fine-grained marine siliciclastics, with the exception of Pleistocene sand, clay, and gravel. The lowest postimpact unit...
Authors
Lucy Edwards, David Powars, J.V. Browning, P.P. McLaughlin, K.G. Miller, A.A. Kulpecz, T. Elbra
Stratigraphy and conodont biostratigraphy of the uppermost Carboniferous and Lower Permian from the North American Midcontinent Stratigraphy and conodont biostratigraphy of the uppermost Carboniferous and Lower Permian from the North American Midcontinent
Part A The uppermost Wabaunsee, Admire, Council Grove, and lower Chase Groups of Kansas, Oklahoma, and Nebraska are placed into three third-order depositional sequences: a Gzhelian late-highstand sequence set, a Council Grove transgressive and highstand sequence set, and a Chase transgressive sequence set. Sequences are defined by bounding maximum-exposure surfaces and are placed within...
Authors
Darwin Boardman, Bruce Wardlaw, Merlynd Nestell
Rock-avalanche and ocean-resurge deposits in the late Eocene Chesapeake Bay impact structure: Evidence from the ICDP-USGS Eyreville cores, Virginia, USA Rock-avalanche and ocean-resurge deposits in the late Eocene Chesapeake Bay impact structure: Evidence from the ICDP-USGS Eyreville cores, Virginia, USA
An unusually thick section of sedimentary breccias dominated by target-sediment clasts is a distinctive feature of the late Eocene Chesapeake Bay impact structure. A cored 1766-m-deep section recovered from the central part of this marine-target structure by the International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) drilling project contains 678 m of...
Authors
Gregory Gohn, David Powars, H. Dypvik, Lucy Edwards
A simulation of historic hydrology and salinity in Everglades National Park: Coupling paleoecologic assemblage data with regression models A simulation of historic hydrology and salinity in Everglades National Park: Coupling paleoecologic assemblage data with regression models
Restoration of Florida’s Everglades requires scientifically supportable hydrologic targets. This study establishes a restoration baseline by developing a method to simulate hydrologic and salinity conditions prior to anthropogenic changes. The method couples paleoecologic data on long-term historic ecosystem conditions with statistical models derived from observed meteorologic and...
Authors
Frank Marshall, G. Wingard, Patrick Pitts
Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth Geologic columns for the ICDP-USGS Eyreville B core, Chesapeake Bay impact structure: Impactites and crystalline rocks, 1766 to 1096 m depth
The International Continental Scientific Drilling Program (ICDP)-U.S. Geological Survey (USGS) Eyreville drill cores from the Chesapeake Bay impact structure provide one of the most complete geologic sections ever obtained from an impact structure. This paper presents a series of geologic columns and descriptive lithologic information for the lower impactite and crystalline-rock sections...
Authors
J. Wright Horton, R.L. Gibson, W.U. Reimold, A. Wittmann, Gregory Gohn, Lucy Edwards
Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin Integrated sequence stratigraphy of the postimpact sediments from the Eyreville core holes, Chesapeake Bay impact structure inner basin
The Eyreville core holes provide the first continuously cored record of postimpact sequences from within the deepest part of the central Chesapeake Bay impact crater. We analyzed the upper Eocene to Pliocene postimpact sediments from the Eyreville A and C core holes for lithology (semiquantitative measurements of grain size and composition), sequence stratigraphy, and chronostratigraphy...
Authors
James Browning, Kenneth Miller, Peter McLaughlin, Lucy Edwards, Andrew Kulpecz, David Powars, Bridget Wade, Mark Feigenson, James Wright
The United States national volcanic ash operations plan for aviation The United States national volcanic ash operations plan for aviation
Volcanic-ash clouds are a known hazard to aviation, requiring that aircraft be warned away from ash-contaminated airspace. The exposure of aviation to potential hazards from volcanoes in the United States is significant. In support of existing interagency operations to detect and track volcanic-ash clouds, the United States has prepared a National Volcanic Ash Operations Plan for...
Authors
Steven Albersheim, Marianne Guffanti
Surface temperatures of the Mid-Pliocene North Atlantic Ocean: Implications for future climate Surface temperatures of the Mid-Pliocene North Atlantic Ocean: Implications for future climate
The Mid-Pliocene is the most recent interval in the Earth's history to have experienced warming of the magnitude predicted for the second half of the twenty-first century and is, therefore, a possible analogue for future climate conditions. With continents basically in their current positions and atmospheric CO2 similar to early twenty-first century values, the cause of Mid-Pliocene...
Authors
Harry Dowsett, Mark Chandler, Marci Robinson
Geological evolution of the Neoproterozoic Bemarivo Belt, northern Madagascar Geological evolution of the Neoproterozoic Bemarivo Belt, northern Madagascar
The broadly east-west trending, Late Neoproterozoic Bemarivo Belt in northern Madagascar has been re-surveyed at 1:100 000 scale as part of a large multi-disciplinary World Bank-sponsored project. The work included acquisition of 14 U-Pb zircon dates and whole-rock major and trace element geochemical data of representative rocks. The belt has previously been modelled as a juvenile...
Authors
Ronald J. Thomas, B. De Waele, D. Schofield, K. Goodenough, M. Horstwood, R. Tucker, W. Bauer, R. Annells, K. Howard, G. Walsh, M. Rabarimanana, J. Rafahatelo, A.V. Ralison, T. Randriamananjara
Comparison of clast frequency and size in the resurge deposits at the Chesapeake Bay impact structure (Eyreville A and Langley cores): Clues to the resurge process Comparison of clast frequency and size in the resurge deposits at the Chesapeake Bay impact structure (Eyreville A and Langley cores): Clues to the resurge process
Collapse and inward slumping of unconsolidated sedimentary strata expanded the Chesapeake Bay impact structure far beyond its central basement crater. During crater collapse, sediment-loaded water surged back to fill the crater. Here, we analyze clast frequency and granulometry of these resurge deposits in one core hole from the outermost part of the collapsed zone (i.e., Langley) as...
Authors
Jens Ormo, Erik Sturkell, J. Wright Horton,, David Powars, Lucy Edwards
Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA Petrographic and geochemical comparisons between the lower crystalline basement-derived section and the granite megablock and amphibolite megablock of the Eyreville B core, Chesapeake Bay impact structure, USA
The Eyreville B core from the Chesapeake Bay impact structure, Virginia, USA, contains a lower basement-derived section (1551.19 m to 1766.32 m deep) and two megablocks of dominantly (1) amphibolite (1376.38 m to 1389.35 m deep) and (2) granite (1095.74 m to 1371.11 m deep), which are separated by an impactite succession. Metasedimentary rocks (muscovite-quartz-plagioclase-biotite...
Authors
Gabrielle Townsend, Roger Gibson, J. Wright Horton, Wolf Reimold, Ralf Schmitt, Katerina Bartosova