Site U1322

The Mars-Ursa salt-withdrawal basin (hereafter referred to as "Ursa Basin") is located 210 km south-southeast of New Orleans, Louisiana (USA), on the northeastern Gulf of Mexico continental slope in 800-1400 m water depth. The 500 and 1000 m bathymetric contours shift to the south in this location and record the center of deposition for late Pleistocene sediments from the Mississippi River. Rapid sedimentation obscured the otherwise hummocky nature of the seafloor in the northern Gulf of Mexico slope. The study area is bounded to the west by Mars Ridge, a prominent north-south-trending bathymetric high. Eastward from Mars Ridge, the seafloor slopes down to a zone of slope failures, including one failure described as one of the largest submarine slope failures in the world (McAdoo et al., 2000).