COMPARISON OF SCARP GEOMORPHOLOGY ALONG THE BLAKE PLATEAU, SOUTHEAST U.S. CONTINENTAL MARGIN

During NOAA’s expeditions Windows to the Deep 2019 and Southeast U.S Deep-Sea Exploration (2019), bathymetric data were collected using multibeam sonar and high definition videos were captured using the ROV Deep Discoverer. Multibeam sonar data were collected during NOAA Ship Okeanos Explorer cruises EX1906 (October), EX1903L1 (June), and EX1907 (November) to produce bathymetric, backscatter intensity and slope surfaces of the seafloor. The purpose of this study was to collect geomorphological information of deep-sea cliff-like scarps on the Blake Plateau, a relatively broad and flat region of the southeast US continental margin. Eight study sites within the Blake Plateau were selected in areas ranging in depth between 800 and 1100m, and geomorphic characteristics of scarps in relatively close proximity were compared. The scarps examined were extremely varied with vertical relief ranging roughly 75 to 200m with an average slope of approximately 13^o. Some scarps exhibit convex profiles while others were terraced with alternating flat and relatively steep slopes ranging approximately 5 to 30^o. High backscatter intensity occurred on flat areas above many scarps, most likely the result of reflection off underlying hard substrate. Scarp ROV dive videos were used to ground-truth geomorphology and benthic life. Comparisons of benthic habitat will be presented. This study provides important information about these important geological and ecological seafloor features found worldwide.