ON THE IMPORTANCE OF GEOLOGIC FRAMEWORK IN UNDERSTANDING COASTAL PROCESSES

An appreciation of the major influence of underlying geologic framework on coastal processes and evolution has only developed in the past decade, and Orrin Pilkey is at its nexus. His call for understanding geologic framework as a prerequisite for understanding coastal processes at societally-relevant time and space scales has not gone unheeded. The USGS is presently conducting regional-scale studies of coastal zone geology, topography and physical processes to understand coastal processes, including erosion and the impacts of shoreline change. Regional coastal studies on the U.S. East Coast include Long Island, New York, northeastern North Carolina, and South Carolina. The data are being used to investigate the role that geologic framework, history of marine transgression, and seabed morphology play in the dynamics of coastal evolution at storm-event to millennial time scales. Results from these studies provide a conceptual framework for ongoing and future studies designed to address the processes controlling nearshore sediment flux and coastal change. These studies have also clearly questioned the validity and applicability of widely used concepts in coastal investigations, such as the shoreface profile of equilibrium and depth of closure.