Optical Dating of Paleoshoreline Features in Northeastern Florida, USA

Optically stimulated luminescence (OSL) age data and ground penetrating radar (GPR) data were acquired from the Atlantic Coastal Ridge (ACR) and the Atlantic Barrier Chain (ABC) provinces in northeastern Florida. The ACR consists primarily of the Anastasia Formation, a coquina that has been previously dated to ~110,000 years before present by Osmond et al. (1970). OSL dating of a coquina or a beachrock has rarely been attempted due to the possible open system nature of the beachrock. We dated three samples of coquina along strike with very promising preliminary results, which appear to coincide with the results of Osmond et al. (1970). An open system model and a closed system model were developed and compared to other ages in the area for comparison. The ABC province sampled consists of a coquina and a beach ridge sequence on eastern Merritt Island. Sea level indicators within beach ridges were identified based upon GPR and sedimentological data, sampled, and dated using a macro-coring system. The results from the ABC province indicate multiple late Quaternary sea-level fluctuations denoted by a wave-cut coquina escarpment and beach ridges that differ in depositional ages. Work is currently being conducted to resolve these issues.