Radiocarbon dates and the genesis of phytogenic near-shore sediments on St. Catherines Island, Georgia, USA

摘要

St. Catherines Island consists of a complex association of Pleistocene and Holocene sediments. The geographic location of the island at the center of Georgia Bight, a prominent re-entrant in the coastline of the southeastern USA, has resulted in the development of a very complex depositional and erosional history. For over 40,000 years the island has experienced a variety of physical, biological, and anthropological changes brought about by climatic, biotic, depositional, and anthropogenic events. Sedimentary deposits have been studied using diverse research tracks including palynology, dendrology, sedimentology, geophysics, and radiocarbon chronology, as well as archaeological techniques. This research focused on the interpretation of environments of deposition of strata that are exposed within the present surf zone, yet which bear the distinct signatures of upland/inland environments of deposition. Data derived from Late Pleistocene and Holocene accumulations of peat and mollusc- and wood-bearing muddy strata of certain on-shore and near-shore origins reveal diverse events relating to shoreline dynamics, plant community changes, and net shoreward migration of this island during the Late Holocene.