Remnants of Sea Level Oscillation in the Shallow Marine Stratigraphy of East-Central Florida

Rising sea level is expected to be one of the most threatening impacts of global climate change in the 21st century, especially in low lying coastal areas such as Florida. Continental shelf stratigraphy is often studied to gain a better understanding of sea-level fluctuation. The research undertaken for this study is based on the assumption that sediments from the lower shoreface and inner continental shelf may provide a detailed record of the sea level fluctuations during the Late Pleistocene Epoch.;Consequently, this study uses flood shoal deposits as a sea level indicator to compare the modem distribution of flood shoal facies to similar facies underlying the inner continental shelf in order to construct a three-dimensional view of inner-continental shelf stratigraphy. To achieve this objective: (1) 22 years of hydrographic data and 46 sediment samples were analyzed; (2) vibracores were collected, logged, and analyzed for texture, fauna, and composition; (3) high frequency sub-bottom acoustic profiles were collected and used to create three-dimensional surfaces.;Lower shoreface and inner continental shelf stratigraphy indicate that Late Pleistocene flood shoals and tidal channels underlie the study area. Above this sequence are north-northwest striking, seaward dipping backbarrier and lagoon sediments consisting of fines, washover, and flood shoal facies.;The results of this study indicate that during the Late Pleistocene, while the Anastasia Formation was deposited west of the modern shoreline, flood shoals developed east of it. After a subsequent drop and rise in sea level, washover sediments dating to ∼41,000 years BP began reaching the study area. Washover sediments gave way to new flood shoal development and lagoon sedimentation before increased shoreline transgression covered the study area in a blanket of washover sediments followed by another interval of lagoon fines. Flood shoals formed rapidly near sea level, providing a potential for use in identifying paleo sea levels in the stratigraphic record. Pleistocene-aged lagoon and transgressive washover sequences extend landward below the transgressive ravinement surface indicating that they predate the latest episode of sea level rise.