Ancient Evidence Offshore: the Search for Prehistoric Human Occupation of South Carolina’s Outer Continental Shelf
Author Dan Brown, MRD Friday, August 28, 2015 - 9:15am
Geologists have observed for decades that drastic changes in the sea level over the past few million years left vast swaths of the modern day sea floor exposed for millennia at a time. Throughout the Pleistocene Era (2.6 million years to 10,000 years ago), the world’s temperature fluctuated between periods known as Interstadial (glacial retreat and warming, causing sea levels to rise) and Glacial (colder temperatures increasing glacier size and lowering sea levels). The Last Glacial Maximum (peak level of glaciation), occurred approximately 20,000 years ago, just before the end of the Pleistocene and during the beginning of the Holocene Era (10,000 years ago to present).
Beginning in the 1980s, Archaeologists speculated that shorelines and valleys where prehistoric humans once lived around the globe are now underwater. Given that human survival requires access to water, and the abundant resources offered by riverine and marine environments, this is not unlikely. The exposure of now submerged land would have allowed prehistoric peoples access to peninsulas, isthmuses, and land bridges to islands otherwise inaccessible; examples include the Aleutian Islands in Alaska, and the isle of Great Britain. Scientists postulate that this is how the first humans migrated into North America and spread across two continents. If this is the case, then evidence of habitation along the coast and likely migration routes ought to exist in now submerged archaeological sites.
What we now call the Outer Continental Shelf (OCS) of the Atlantic Ocean was once the prehistoric coastal plain. Random finds by fishermen and divers on the OCS have revealed evidence of coastal habitation sometime after the Last Glacial Maximum. This habitation lasted until complete inundation (the terminus of sea level rise) approximately 14,000 through 6,000 years ago. During the inundation of the ancient coastal plain by the Atlantic Ocean, prehistoric peoples would have migrated inland gradually settling on the modern coastal plain. Occupation of the modern coastal plains reveals hundreds of sites and artifacts suggesting constant habitation for thousands of years. This in turn suggests that prehistoric peoples would have occupied the now drowned coastal plain in a similar manner creating hundreds of additional sites.
Once, this was merely a theory put forth by a minority of paleo archaeologists backed up only by incidental finds by people involved in fishing, sport diving, and dredging.
The technology to detect such submerged habitation sites would take years to develop, mostly through efforts mapping the sea floor of the world’s oceans. As technological advances in oceanographic survey advanced, so did the possibility of a scientific and systematic effort to try to locate submerged paleo-archaeological resources. Since the early 2000s, numerous such projects have been completed across the globe. The result is the creation of an entirely new sub-discipline of archaeology. Experts in oceanography, paleo-archaeology, geology, and remote sensing technology must all work together to accomplish the enormous task of surveying vast areas of OCS for evidence of occupation.
In 2014, South Carolina joined a growing number of Atlantic states interested in the possibility of offshore Wind Energy Areas (WEA). North Myrtle Beach, having introduced small wind turbines years ago, pushed for a successful agreement between the Bureau of Ocean Energy Management (BOEM) and the state of South Carolina. The project aims to survey areas 11 to 16 miles offshore the town ranging from Little River Inlet to Georgetown off Cape Romain. The South Carolina BOEM Cooperative Agreement, as its termed, involves multiple state entities and universities working together to conduct oceanographic survey of the areas designated as potential sites for WEA to be leased and developed in the future. Concurring with the requirements of the National Historic Preservation Act (NHPA), BOEM is responsible for making sure that no submerged cultural resources would be harmed or destroyed by future energy development. This is where SCIAA and the Maritime Research Division (MRD) come in. Since part of the survey is in state waters, Costal Carolina University (CCU), which is leading the survey with their research vessel Coastal Explorer, is working in tandem with University of South Carolina’s Earth Sciences Resource Institute (ESRI), and the College of Charleston to collect and interpret data for potential historic and prehistoric archaeological sites . Developing a list of potential historic shipwrecks and predictive model for submerged prehistoric sites has been delegated to MRD. As the survey continues to collect data on the seafloor off South Carolina, MRD plans to work with CCU and BOEM to dive and inspect targets for potential historic and prehistoric sites later this fall. Searching the ocean’s floor for prehistoric evidence in the form of shell middens, potsherds, or stone points might be the equivalent of searching for a needle in a field of hay stacks, howeve, archaeologists hope to use information from South Carolina’s thousands of terrestrial prehistoric sites to predict what geological features might yield the best possibility of locating a submerged prehistoric site. What the survey uncovers will be exciting for both the archaeological community and the public at large. Ultimately, the survey will recommend where future WEA development can take place and what areas developers should avoid so as to preserve South Carolina’s submerged cultural heritage.
For more information on submerged paleo archaeology and Paleo-Indian sites see the links below:
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Underwater Archaeology Paleolandscapes Geology BOEM