Possible Interchange of Sediments between a Beach and Offlying Linear Shoal

Abstract

Source: https://erdc-library.erdc.dren.mil/jspui/An investigation of Gilbert Shoal, a typical nearshore linear shoal on the Florida Atlantic coast, was undertaken to determine if significant interchange of sediments occur between the shoal, the surrounding seafloor, and the adjacent beach. The principal technique of study made use of selected sediment particle types or particular characteristics such as natural tracers. Sever tracer elements and two particle characteristics were of some use. It was found that some sediment from the shoal reaches the beach, but the amounts involved are small and most of the beach sediment comes from littoral drift, organic shell production on the lower beach and nearshore area, and breakdown of coquina rocks of the Anastasia Formation which crop out on the beach and in the nearshore zone. Gilbert Shoal and the surrounding sea floor apparently recieve little, if any sediment from the beach or nearby St. Lucie Inlet. Gilbert Shoal sediment appears to be derived from the nearby shelf floor and from in situ shell production