Geologic Mapping of the Massachusetts Seafloor

Science Center Objects

The U.S. Geological Survey, in cooperation with the Massachusetts Office of Coastal Zone Management (CZM) is conducting geologic mapping of the sea floor to characterize the surface and shallow subsurface geologic framework within the Massachusetts coastal zone. The long-term goal of this mapping effort is to produce high-resolution geologic maps and a Geographic Information System (GIS) that will serve the needs of research, management and the public. This project page provides a description of the mapping program and links to data  and publications  produced for this project and other Massachusetts  mapping efforts. Link to interactive map.

Image showing a study area from Boston Harbor to the mouth of Cape Cod

Image showing a study area from Boston Harbor to the mouth of Cape Cod Bay including some images of geophysical and sample data available in the associated report.

Geologic mapping of the Massachusetts inner continental shelf is a cooperative effort that was initiated in 2003 by the U.S. Geological Survey (USGS) and the Massachusetts Office of Coastal Zone Management (CZM).  The National Oceanic and Atmospheric Administration – National Ocean Service (NOAA-NOS) is also an important partner and contributes hydrographic data that are integrated into the maps. The overall goal of this cooperative is to determine the geologic framework of the sea floor within the Massachusetts coastal zone, using high-resolution geophysical techniques, sediment sampling, and sea floor photography. Water depths in the study area range from about 2 m (6 ft) along the coast to 90 m(295 ft) in offshore areas.

The products and knowledge developed by this project have broad application to regional science and resource-management issues. The geologic and bathymetric maps help us understand the processes that have shaped the coast and how it has evolved over time, and thereby help evaluate the vulnerability of coastal environments to storms, sea-level rise, and long-term climate change. Accurate maps that depict the distribution of bottom types on the inner continental shelf provide scientific guidance for appropriately siting offshore development such as sand mining, pipelines, and renewable energy projects. The Massachusetts Division of Marine Fisheries (DMF) uses the maps to monitor habitat recovery following pipeline construction in Massachusetts Bay and to conduct fisheries research. Ultimately, these maps will support the Massachusetts Ocean Management Plan, an integrated, multi-use, proposal for the management of Massachusetts waters.

map of acoustic backscatter intensity of the seafloor in Buzzards Bay, MA

Acoustic backscatter intensity data are an indication of the relative hardness or softness of the sea floor, which is closely related to sediment texture and cohesion. The map shows acoustic backscatter intensity of the sea floor in the Buzzards Bay, Massachusetts. In general, higher values (light tones) represent rock, boulders, cobbles, gravel, shell reefs, and coarse sand. Lower values (dark tones) generally represent fine sand and muddy sediment. Within Buzzards Bay, high acoustic backscatter is most often associated with glacial  deposits, such as moraines and meltwater fans. Low acoustic backscatter in the basins of Buzzards Bay are Holocene marine and estuarine muddy deposits.