DEVELOPING PROXIES FOR LATE HOLOCENE SEA-LEVEL AND CLIMATE CHANGE ALONG THE NORTHEASTERN GULF OF MEXICO COAST

An investigation on the northern Gulf of Mexico coast has developed sea-level and climate proxies for the late Holocene. The goal was to better understand the relationship between climate change and fluctuations in sea-level and storm frequency. The study site was St. Vincent Island, a barrier beach ridge plain on the northwestern coast of Florida. The data sources were a ground-penetrating radar (GPR) transect across the island, and a sediment core from Oyster Pond, a coastal lake within the beach ridge plain. Through analysis of the GPR data, along with optically stimulated luminescence (OSL) dating, a technique was developed for determining paleo-sea level, based on the depth of basal deposits of the ridges in the beach ridge succession. The sedimentary parameters of the lake core were used to identify periods of enhanced storminess. Core chronology was determined through Pb-210 and C-14 dating methods. Using historic storm tracks and storm surge data, a storm signature in the sediment profile was developed. This sedimentary signature was utilized to identify periods of storminess. In addition, storm surge heights for the identified paleo-storm periods were calculated to estimate storm intensity.