SEM-EDS AND XRD-WDS CHARACTERIZATION OF UNCONVENTIONAL PREHISTORIC ARTIFACTS FROM THE SOUTHEASTERN U.S. CONTINENTAL SHELF, GRAY'S REEF NATIONAL MARINE SANCTUARY, GEORGIA

Scanning electron microscopy, electron dispersive spectroscopy (SEM-EDS) and wavelength dispersive x-ray diffraction (XRD-WDS) examinations of artifacts and outcrops recovered during archaeological survey at Gray’s Reef National Marine Sanctuary, located 32 km offshore from Georgia, in the South Atlantic Bight, are discussed here. These artifacts- a subfossil bone/antler tool and two lithic tools: a projectile point typologically assigned to the Middle Archaic Period (~8000 BP - ~5000 BP) and a crude, unifacial flake scraper are both made of a somewhat atypical lithic material- a dolomitized/biomicritic calcarenite. Geoarchaeological studies since 1996 at Gray’s Reef have detailed the geology of this location, and have supported a hypothesis that post-glacial sea level rise overstepped Gray’s Reef’s 17 to 20 meter depths ca. 8000 BP. Gray’s Reef was a subaerial coastal plain prior to this date for roughly 30 millennia. Petrological and geochemical data from the stone tools were compared to one another, as well as to samples from four outcrops adjacent to where the tools were recovered. These findings indicate that the stone tools were not made from rocks of the type of outcrops found at Gray's Reef. Furthermore, the data demonstrate that these tools are not made of the same source material. This strongly suggests human agency in their transport to Gray’s Reef. The source for the lithic materials used for these artifacts is yet to be determined.