Publications
Filter Total Items: 834
Scanning electron microscope images of sand and silt from the early MIS4–MIS3 Roxana Silt, Phillips Bayou, Arkansas
The age and source of the late Pleistocene Roxana Silt in the Mississippi Valley have been studied since the middle 1800s. Published age and paleoenvironmental data for the Roxana Silt in the Mississippi Valley show that deposition occurred from late marine isotope stage 5 (MIS5) through late marine isotope stage 3 (MIS3) (80–30 kilo-annum [ka]), when the warm to hot interglacial climate of early
Authors
Helaine W. Markewich, Douglas A. Wysocki, G. Norman White, Joe B. Dixon
Roles of climatic and anthropogenic factors in shaping Holocene vegetation and fire regimes in Great Dismal Swamp, eastern USA
The Great Dismal Swamp wetland, spanning >400 km2 along the Virginia and North Carolina border, was shaped by a complex combination of geomorphic, climatic, and anthropogenic forcings during the last 14,000 years. Pollen, macrofossils, charcoal, and physical properties from sediment cores at seven sites provide a detailed record of the spatial heterogeneity of the wetland and the roles played by n
Authors
Debra A. Willard, Miriam C. Jones, Jay R. Alder, David Fastovich, Kristen Hoefke, Robert Poirier, Fred C. Wurster
Geology and paleontology of Cretaceous and Paleocene sediments of the Cabin Branch, Cabin Creek (Cappy Avenue), and Tinkers Creek outcrops, Prince George’s County, Maryland
This field guide presents a one-day excursion in Prince George’s County, Maryland, USA, and documents the transition across the Cretaceous-Paleogene boundary by examining sediments from the upper Maastrichtian of the Severn Formation to the Paleocene sediments of the Brightseat and Aquia formations. Emphasis is placed on understanding how differences in depositional character and lithostratigraphy
Authors
Jean Self-Trail, David L. Govoni, Laurel M. Bybell, Kristina Frank Gardner
Rift basins and intraplate earthquakes: New high-resolution aeromagnetic data provide insights into buried structures of the Charleston, South Carolina seismic zone
The delineation of faults that pose seismic risk in intraplate seismic zones and the mapping of features associated with failed rift basins can help our understanding of links between the two. We use new high-resolution aeromagnetic data, previous borehole sample information, and reprocessed seismic reflection profiles to image subsurface structures and evaluate recent fault activity within the Ch
Authors
Anjana K. Shah, Thomas L. Pratt, J. Wright Horton,
Evaluation of management efforts to reduce nutrient and sediment contributions to the Chesapeake Bay estuary
No abstract available.
Authors
Z. Easton, K. Stephenson, B. Benham, John K. Böhlke, A. Buda, A. Collick, L. Fowler, E. Gilinsky, C. Hershner, Andrew Miller, Gregory Noe, L. Palm-Forster, T. Thompson
Achieving water quality goals in the Chesapeake Bay: A comprehensive evaluation of system response
A Comprehensive Evaluation of System ResponseAchieving Water Quality Goals in the Chesapeake Bay: A Comprehensive Evaluation of System Response (CESR) includes an evaluation of why progress toward meeting the TMDL and water quality standards has been slower than expected and offers options for how progress can be accelerated. This report is a summation of a three year investigation into the 40 yea
Exploring the influence of input feature space on CNN-based geomorphic feature extraction from digital terrain data
Many studies of Earth surface processes and landscape evolution rely on having accurate and extensive data sets of surficial geologic units and landforms. Automated extraction of geomorphic features using deep learning provides an objective way to consistently map landforms over large spatial extents. However, there is no consensus on the optimal input feature space for such analyses. We explore t
Authors
Aaron E. Maxwell, William Elijah Odom, Charles M. Shobe, Daniel H. Doctor, Michelle S. Bester, Tobi Ore
Rapid estimation of minimum depth-to-bedrock from lidar leveraging deep-learning-derived surficial material maps
Previously glaciated landscapes often share similar surficial characteristics, including large areas of exposed bedrock, blankets of till deposits, and alluvium-floored valleys. These materials play significant roles in geologic and hydrologic resources, geohazards, and landscape evolution; however, the vast extents of many previously glaciated landscapes have rendered comprehensive, detailed fiel
Authors
William Elijah Odom, Daniel H. Doctor
Multi-proxy record of ocean-climate variability during the last 2 millennia on the Mackenzie Shelf, Beaufort Sea
A 2,000 year-long oceanographic history, in sub-centennial resolution, from a Canadian Beaufort Sea continental shelf site (60meters water depth) near the Mackenzie River outlet is reconstructed from ostracode and foraminifera faunal assemblages, shell stable isotopes (delta 18O, delta 13C) and sediment biogenic silica. The chronology of three sediment cores making up the composite section was es
Authors
Laura Gemery, Thomas M. Cronin, Lee W. Cooper, Lucy Roberts, Lloyd D Keigwin, Jason A. Addison, Melanie Leng, Peigen Lin, Cedric Magen, Marci E. Marot, Valerie Schwartz
Unzipping supercontinent Pangea: Geologic, potential field data, and buried structures, and a case for sequential Atlantic opening
Amalgamation of Pangea culminated with zippered N-to-S closing of the Theic ocean during the Alleghanian orogeny. Transpressional-rotational collision produced widespread dextral faulting throughout the eastern Appalachian hinterland, and thrust faulting in the western hinterland and foreland. The partially buried southern Appalachian Eastern Piedmont fault system is a product of late Paleozoic tr
Authors
Aaron G. Stubblefield, Robert D. Jr. Hatcher, J. Wright Horton,, David L. Daniels
Investigating geomorphic change using a structure from motion elevation model created from historical aerial imagery: A case study in northern Lake Michigan, USA
South Manitou Island, part of Sleeping Bear Dunes National Lakeshore in northern Lake Michigan, is a post-glacial lacustrine landscape with substantial geomorphic changes including landslides, shoreline and bluff retreat, and sand dune movement. These changes involve interrelated processes, and are influenced to different extents by lake level, climate change, and land use patterns, among other fa
Authors
Jessica D. DeWitt, Francis Ashland
Redefinition of the Petersburg batholith and implications for crustal inheritance in the Dinwiddie terrane, Virginia, USA
Field relations as well as geochemical and petrologic studies of metaigneous rocks assigned to the Pennsylvanian–Permian Petersburg batholith identify at least two distinct rock types: foliated metagranitoid gneiss and massive to porphyritic granite. Foliated metagranitoid gneiss of mostly granodioritic composition is geochemically distinct from associated massive and porphyritic granitic rocks. T
Authors
Mark W. Carter, Ryan J. McAleer, Christopher Holm-Denoma, Marcie E. Occhi, Brent E. Owens, Jorge A. Vazquez