Alternate Leg ID: GYRE 82-G-10; 82-10A,B
Area of Operations: middle Atlantic Bight, Continental Rise and Slope, Lindenkohl Canyon, Toms Canyon, New Jersey, Baltimore Canyon, Maryland, Delaware, Pamlico Sound, North Carolina, United States, North America, North Atlantic
Dates: August 26, 1982 to September 14, 1982
Objectives: Single-channel seismic reflection survey of the continental rise and continental slope and rise portions of 2 submarine canyons on the U.S. south and mid-Atlantic continental margin to define sea floor morphology and processes.
Type of Activity: Seismic profiling
Information to be derived: Morphology
Summary: The purpose of the first part of this cruise (82-G-10A) was to investigate the upper Continental rise between Lindenkohl and Toms Canyon, offshore New Jersey, using seismic reflection profiling and deep-towed hydrophone profiles. About 800 km of trackline were profiled using single-channel airguns. Airgun records are excellent, showing as much as 1.4 seconds of penetration. Attempts to acquire deep towed hydrophone profiles were unsuccessful. The phone did not reach close enough to the sea bottom. Teledyne minisparker was discontinued after about 600 km of profiles to avoid interference with airgun data. Use of an EDO 4077 narrow beam echo sounder was discontinued after about 56 hours when bungee cords making up its towing harness failed. The purpose of the second part of the cruise (82-G-10B) was to evaluate canyon processes on the slope and rise using seismic reflection profiling systems (airgun and 3.5 kHz). Minisparker data were not collected to avoid interference with the airgun data. The survey in the Baltimore Canyon area extends to the adjacent slope and rise. Excellent airgun profiles provide approximately 1 second of penetration for evaluation of canyon processes in the geologic past. The survey of the canyon seaward of Pamlico Sound provides detailed bathymetric and seismic reflection profile data of a canyon on the U.S. south Atlantic margin for comparison with those canyons surveyed on the U.S. mid- and north Atlantic margins, and an opportunity to evaluate the influence of ocean circulation on canyon processes. During the survey the Gulf Stream was located over the lower slope and rise in the area. The sea state during the survey decreased the acoustic penetration on the airgun profiles at times from 0.8 seconds to 0.4 seconds, and also decreased the clarity of the 3.5 kHz data.
USGS Project Number: 9840-02806 9840-01822
Contact: Bonnie McGregor ()
Map for Area of Operations :