Late Pleistocene-Holocene age and stratigraphy of the Currituck Slide Complex, U.S. mid-Atlantic continental slope: Implications for landslide triggering

Considerable effort has been made to link submarine slope failures to changes in local and global-scale environmental conditions, in order to assess landslide hazard probability. Here we provide the first radiocarbon dates of hemipelagic sediment overlying mass transport deposits and inferred failure surfaces of the Currituck Slide Complex (CSC), a prominent landslide scar on the U.S. mid-Atlantic continental slope. The dates, taken from both the upper and lower scars of the complex, constrain the age of the last major failure event to 13,835 and 16,020 years BP. Time correlation of the hemipelagic sediments across the landslide scar and proximal deposit suggests a single failure of both the upper and lower parts of this 160 km3 volume. A higher rate of sediment supply from the periglacial Appalachian Mountains and from glacial melt-water pulses, with an exposed continental shelf at that time, may have enlarged a shelf-edge delta at the site of the CSC, which may have facilitated or triggered failure. A smaller landslide at the southern edge of the complex with a less well-defined geomorphologic footprint is dated at 5500 BP and possibly represents the reshaping of the seafloor around the CSC triggered by low-frequency earthquakes on the nearby continental margin.