The Geologic Implications of the Factors that Affected Relative Sea-level Positions in South Carolina During the Pleistocene and the Associated Preserved High-stand Deposits
This work utilizes the current understanding of South Carolina geology to provide a stratigraphic review of the late-Pliocene and Pleistocene marine deposits. Almost two centuries of recorded geological study includes geomorphic and stratigraphic units that were described, proposed, revised, abandoned, and revived. Along with the history of the age assignments, changes in geological time scales, and the changes in the understanding of geological concepts, this review is necessary because two concurrent and conflicting stratigraphies exist for late-Pliocene and Pleistocene marine sediments that record multiple sea-level transgressions that were more often destructive than constructive. The result, when tested against existing geological data covering \u3e22,000 km2, is a set of interpretations providing a revised and unified geomorphic and stratigraphic nomenclature. Eleven stratigraphic units occur only in the subsurface. Ten Plio-Pleistocene highstand deposits are preserved at the surface: one Pliocene, eight Pleistocene, and the current transgression. When the Pleistocene highstand elevations and geochronology were compared to sea-level reconstructions, based on predicted elevations from marine isotope studies, only two highstands matched. Other observed highstand elevations are higher than predicted by reconstructions. The factors affecting relative sea-level changes were studied to rectify the gap between the observed and predicted elevations. When applied, the factors partially reduce the gap; however, the results suggest that the processes affecting post-depositional changes in shoreline elevations are complex and not completely understood
