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To assess surficial geologic conditions of importance to exploration and development of the continental slope off New Jersey, the U.S. Geological Survey has mapped the area between Lindenkohl and South Toms Canyons (including blocks to be leased in Sale No. 59). A dense network of high-resolution seismic reflection profiles and more than 65 piston cores shows a complex bathymetric surface underlain by Pleistocene sediments on the upper slope and midslope. Tertiary sediment crops out on the lower slope. The seismic profiles, piston cores, and observations from several submersible dives on the uppermost slope suggest that the slope, now generally blanketed by a thin layer of fine-grained Holocene sediment, is relatively quiescent, but was geomorphically more active during t e late Pleistocene or early Holocene. In contrast, more recently acquired images from a deep-towed midrange sidescan-sonar system (5 km swath) show geomorphic details of gullied canyon walls, differential erosion of truncated strata, several small slope failures, and apparent amphitheatric headward erosion of lower slope valleys. An area of the upper continental rise is covered by blocky debris which may have been transported down South Toms Canyon. The "crispness," shapes, and locations of such features detailed by the sidescan-sonar images suggest that some of these features may be recent. Additional observations to investigate the nature and age of these features on the midslope and lower slope were conducted from the deep-diving submersible Alvin during July 1981.
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