The geologic framework of the Massachusetts inner continental shelf between Nahant and Gloucester has been shaped by a complicated history of glaciation, deglaciation, and changes in relative sea level. New geophysical data (swath bathymetry, sidescan sonar and seismic-reflection profiling), sediment samples, and seafloor photography provide insight into the geomorphic and stratigraphic record generated by these processes. Approximately 325 km² (125 mi²) of shallow seafloor were mapped, focusing on nearshore areas from the coast out to water depths of about 90 m (295 ft).
The maps were produced as part of a cooperative mapping program between the U.S. Geological Survey (USGS) and Massachusetts Office of Coastal Zone Management (CZM). Additional project partners include University of New Hampshire (UNH) - Center for Coastal and Ocean Mapping (CCOM), Boston University, and the Massachusetts Division of Marine Fisheries. Accurate depictions of seafloor geology are an important first step toward understanding the type, distribution, and quality of subtidal marine habitats in the Massachusetts coastal ocean. The main objective is to support marine resource managers charged with making decisions on the use and protection of ocean resources. A companion report (in press, November 2009) will contain descriptions of the data collection, processing, and analysis procedures used to create the maps, and GIS databases with all the geophysical and ground-validation data collected as part of this study.
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Overview of the Cape Ann - Salisbury Beach survey area showing shaded relief bathymetry colored by water depth. Click on figure for larger image. |
Preliminary Results
For more information:
Walter Barnhardt
U.S. Geological Survey
Woods Hole Science Center
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
wbarnhardt@usgs.gov
Brian Andrews
U.S. Geological Survey
Woods Hole Science Center
384 Woods Hole Rd.
Woods Hole, MA 02543-1598
bandrews@usgs.gov
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