Summary Information for Field Activity 1970-007-FA

Area of Operations: western Gulf of Maine, Jeffreys Ledge, Jeffreys Basin, Casco Bay, Massachusetts Bay, Cape Cod Bay, Stellwagen Bank, Massachusetts, New Hampshire, Maine, United States, North America, North Atlantic

Dates: June 10, 1970 to June 16, 1970

Chief scientist: John Schlee

Objectives: The main purpose was to complete bottom sediment sampling in the nothern quadrangle and to do additional 3.5 kHz seismic profiling as a supplement to those taken in earlier cruises of the GOSNOLD and VERRILL last year.

Type of Activity: Sampling; Seismic profiling;

Information to be derived: Grain size analysis;

Summary: A total of 154 stations were occupied during the seven days at sea. The GOSNOLD steamed a total of 691 miles during which we obtained approximately 600 miles of sonic profiles. Samples were taken 2-4 miles apart and were selected utilizing a 1/40,000 scale bathymetric map of the sea floor compiled by the Coast & Geodetic Survey. Selection was key to a variety of topographic features in the area, some only a few hundred meters across. Despite very complex topography, the type of sediment was restricted to relatively few types - broadly outlining topographic provinces rather than particular features. Sonic profiles showed penetration 20 fms over soft bottom and a multilayered arrangement of reflecting horizons over basins. Some of the reflectors appear to pinch out toward the basin edge or to have an erosional pinch out at the edge.

Contact: John Schlee (jschlee@usgs.gov)

InfoBank: uses the identifier G-64-70-NE. Visit this site for more information.

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