Interpretation of the thickness of the upper-most mappable unit, Holocene u1, within the Hudson Shelf Valley, derived from seismic data collected by the U.S. Geological Survey, 1995 - 1999 (Grid, UTM Zone 18N, WGS84)

In 1995, the U.S. Geological Survey (USGS), in cooperation with the U.S. Army Corps of Engineers (USACE), began a program to generate reconnaissance maps of the sea floor offshore of the New York - New Jersey metropolitan area and within the southern Long Island nearshoe area. Our methods include high-resolution sidescan sonar and subbottom profiling techniques, along with surface grab and vibracore sampling to verify the geophysical interpretations. The goal of the investigation is to provide a regional synthesis of the sea-floor environment, to determine regional-scale availability of sand as a resource for beach nourishment programs, and to investigate the role that inner-shelf morphology and geologic framework have in the evolution of the coastal region within the New York Bight Apex and southern Long Island. Maps derived from interpretation of the subbottom profiles show information on the geometry and distribution of the Quaternary sediments and the underlying coastal-plain unconformity. This seismic stratigraphy yields a regional framework on which explanations of present (and past) sediment movement, dispersal, and erosion processes are based.