Other ID: GYRE 82-G-10; 82-10A,B
Organization(s): USGS, Woods Hole Coastal and Marine Science Center
Location: 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;
Principal Investigator(s): Bonnie McGregor, James M. Robb
Data Type(s): Electro-Magnetic: Gravity, Location-Elevation: Navigation, Seismics: Air Gun / Water Gun, Seismics: Boomer, Seismics: Bubble Gun, Seismics: Sparker, Seismics: Sub Bottom Profiler, Sonar: Single Beam
Scientific Purpose/Goals: 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.
Start Date: 1982-08-26
Start Port/Location: Woods Hole, MA
End Date: 1982-09-14
End Port/Location: Morehead City, NC
Equipment Used: Teledyne single-channel 300-500J 40-tip minisparker, Teledyne 28420 hydrophone, 3.5 kHz, 12 kHz, EDO 4077 narrow beam echo sounder, Water gun (wh), Gravity meter (wh), Integrated Navigation System
Information to be Derived: Morphology;
Summary of Activity and Data Gathered: 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.
Staff: Candy Bostwick, Paul Bowker, James E. Dodd, John C., Jr. Hampson, Barry Irwin, David Mason, Bonnie McGregor, Gregory Miller, James M. Robb
Notes: Original Center People field contained: Bonnie McGregor - co-Ch. Sci., James Robb - co-Ch. Sci.; Paul Bowker, James Dodd, John Hampson, Barry Irwin, Eric Koelsch, Candy Lane, David Mason, Greg Miller, Joann Brendt Taylor, Susan Williams. Original Submitted By field contained: Bonnie McGregor, James Robb.