A 5,000-YEAR PALEOSTORM RECORD FOR THE NORTHWEST FLORIDA COAST

A new technique has been developed for identifying storm signatures in coastal lake sediments and establishing the geologic record of storm occurrence. A sediment core from a northwest Florida coastal pond, representing the past five millennia, was subjected to high resolution sedimentologic and stable isotope analysis, complemented by geochronology and micropaleontology. The data were input to a statistical storm model, based on two geochemical sediment variables (δ¹³C and % N′) and one physical sediment variable (% sand), developed in another lake in the region and calibrated with historic storm and long-term tide gauge records. The storm model identified both storm events and storm clusters in the sediment record. The results were then analyzed to develop a quantitative estimate of the number of storms per century. The modeled storm events separate into 4 periods of increased storminess, ranging from as few as 4 storms per century to as a many as 10 storms per century. This study quantifies the long-term storm history for the northwest Florida coast and represents a tool for better understanding the real storm hazard risk for coastal regions.