ATLANTIC OFFSHORE WIND ENERGY DEVELOPMENT: GEOPHYSICAL MAPPING AND IDENTIFICATION OF PALEOLANDSCAPES AND HISTORIC SHIPWRECKS OFFSHORE SOUTH CAROLINA

The Bureau of Ocean Energy Management (BOEM) has identified potential wind energy areas (WEA) on the continental shelf of South Carolina characterized by good wind resource potential and minimal environmental and societal use conflicts based on existing regional data sets. A multi-sensor geophysical survey has been initiated to provide a more thorough determination of the shallow geologic framework and bottom habitat and cultural resources potential to further refine future wind farm siting. The study is focused on two areas: the inner shelf from 18 to 26 km offshore of North Myrtle Beach, SC and a second smaller area offshore of Georgetown, SC. The collaborative effort is generating 100% multibeam and side scan sonar coverage and chirp sub-bottom and magnetometer data on 180 meter line spacing. The 10-km wide swath parallels a similar high-resolution geophysical survey from the shoreline to 8 km offshore, from the North Carolina Border to Winyah Bay, completed as part of the joint USGS- SC Sea Grant South Carolina Coastal Erosion Study. Across the region a thin veneer of sediment overlies indurated tertiary deposits. The Tertiary geologic section is locally scoured and influenced by small channels and probable karstification and enduring fluid exchange across the sea floor which has been previously identified in the region. The sea floor exhibits large-scale (100s of meters) low relief shore-perpendicular bedforms similar to those found within the shoreface and innermost shelf through the SC Coastal Erosion Study. Central to the WEA study is the realization that the Outer Continental Shelf (OCS) has the potential to yield a wealth of archaeological information about the early peopling of North America and the historic seafaring traditions of exploration, trade, and warfare. Preliminary project findings suggest that three historic shipwrecks have been located, with on-going efforts to identify paleolandforms bearing the potential to contain evidence of human habitation.

Following the initial regional mapping, site-specific groundtruthing will be undertaken in the spring and summer of 2016.