Submarine mass-wasting of sediments on the continental slope and upper rise south of Baltimore Canyon

Abstract

Detailed bathymetric and high-resolution 3.5-kHz surveys as well as submersible-based visual observations carried out on the U.S. continental margin off Delaware Bay have delineated a complex pattern of incised valleys with a 50-m-thick layer of acoustically laminated sediments draping the ridges. Sediment slides have moved much of this unit along acoustically well-defined glide planes and deposited it in the valleys of the upper continental rise. These deposits are acoustically unlayered and can be mapped as a sheet deposit over an area of more than 2000 km 2 and to a water depth of 2900 m. Sediment cores and submersible observations have shown no evidence for recent slope failures at the locations the observations were made.