GEOMORPHOLOGY AND PRELIMINARY OPTICAL DATING ON PALEOSHORELINE FEATURES IN NORTHERN FLORIDA, USA

Ground penetrating radar (GPR), optically stimulated luminescence, and electron spin resonance optical dating techniques are being applied to key paleoshorelines features throughout northeastern and northwestern Florida in an attempt to determine depositional environments as well as depositional age. These features are grouped into three sequences as defined by Winker and Howard (1977), the Chatham Sequence, the Effingham Sequence, and the Trail Ridge Sequence. A fourth sequence, labeled the Apalachicola Sequence is also being studied. GPR data is being used to define their sequence stratigraphy by identifying target reflectors and lithofacies for subsequent coring and luminescence dating. Such units already identified in preliminary work include seaward prograding beach ridge foreshore deposits, backshore and aeolian sands, and paleosols. The ages of many of these siliciclastic deposits in Florida are largely unknown and/or highly debated in literature due to the lack of reference fossil availability or datable material. Preliminary luminescence dates indicate a complex Plio-Pleistocene sea-level history of shoreline reoccupations, flooding events, and Holocene dune reactivations. These reactivations have been identified from Florida to Delaware, suggesting a regional event of sand sheet movement.