New Regional-Scale Geophysical Observations of the Delmarva Peninsula, U.S.A. Inner Continental Shelf

Tuesday, 16 December 2014
Laura L. Brothers, E Robert Thieler, Elizabeth A Pendleton, David S. Foster, William W Danforth, Wayne E. Baldwin and Seth D. Ackerman, US Geological Survey, Woods Hole, MA, United States
The Delmarva Peninsula is a 220-kilometer-long headland, spit and barrier island complex located in the central Mid-Atlantic Bight. This region’s antecedent geology, sediment type and distribution, deposit geometry, and transport pathways are poorly constrained. Here we present preliminary findings from chirp and 16-channel boomer seismic reflection profiles, swath bathymetry, acoustic backscatter data and sediment samples collected in June-July, 2014, over 3220 km2 of the inner continental shelf. These co-located datasets characterize the broad-scale geologic framework of the central offshore Delmarva Peninsula, and also provide the geologic underpinnings to National Ocean Service (NOS) hydrographic bathymetry and previously unpublished acoustic backscatter data collected in the region between 2007 and 2011. The combined datasets extend 100 km along the coast from approximately the 8-m isobath to 30 km offshore in water depths up to ~ 30 m. They provide unprecedented resolution and spatial coverage of an inner continental shelf environment along the U.S. eastern seaboard. Analyses of these high-resolution datasets will improve understanding of inner continental shelf features and processes including: shoal massif origins, sand-ridge development, barrier-island system migration, shallow natural gas occurrence and distribution, paleochannel evolution, regional sea-level history and the role of antecedent geology in the central Delmarva coastal system. In addition to scientific insights, these data provide the foundation for a variety of management applications, such as sand resource, habitat, and coastal vulnerability assessments.