Sedimentary processes and depositional history of a cape-associated shoal, Cape Lookout, North Carolina

The sedimentary processes of a cape-associated shoal are an integral component of the sediment budget of the surrounding cuspate foreland shoreline. The manner in which sediment is delivered to a shoal and the fate of this sediment, once delivered, have important implications to shoreline management and yet remain largely unstudied. Modern sedimentary processes and the recent depositional history of Cape Lookout Shoal, a large cape-associated shoal in the mixed-energy environment of the North Carolina continental shelf, were examined in a field-intensive study through high-resolution seismic profiles, hydraulic probes, near-bottom current meters, sediment grab samples, and detailed bathymetric surveys. Our findings indicate that: (1) the sediment budget of the up-drift littoral cell is coupled directly to Cape Lookout Shoal, (2) the sedimentary processes of the shoal remain active down its entire length but at a diminishing level with distance from the shore, and (3) the shoal serves as a long-term sink for littoral-zone sediment and limits sediment exchange between adjacent littoral cells and shelf regions. We present evidence suggesting that the position and morphology of Cape Lookout Shoal are not controlled by underlying erosion-resistant strata and that the shoal appears to have developed in the late Holocene after the shelf was scoured by the transgressing shoreface.