Developing a Microfossil-based Approach to Estimate Paleo-Hurricane Intensity
Andrea Hawkes, Geology & Geophysics Jeffrey Donnelly, Geology & Geophysics
Funded Project 2010:
Currently efforts to estimate hurricane intensity (storm surge and wave magnitude) from sedimentary records of overwash have been speculative. This project focuses on examining the potential use of marine microfossil assemblages in overwash sediments as indicators of hurricane intensity in the Florida Panhandle using instrumental, historic and modeled data as validation. We have identified historic hurricane stratigraphies in coastal ponds (Mullet Pond and nearby sites) which have a high sensitivity to hurricane overwash along Apalachee Bay, FL. A hurricane overwash record developed from radiocarbon dated sediment cores collected from Mullet Pond provides temporal resolution for as many as 177 hurricane deposits in the last 4500 years (3.9 events per century) with at least 8 storms occurring in the historic period since 1851. Preliminary data from Mullet Pond suggests that offshore foraminifera preserved in some storm induced layers may be a valuable proxy for differentiating more intense hurricane strikes. With further analysis of a series of offshore transects we will develop a distribution map of benthic foraminifera to determine the depth and distance of wave excavation for hurricane-induced overwash layers which circumvents uncertainty relating to changes in barrier height. If this approach proves to be viable it will provide essential data on past patterns of hurricane activity, providing a critical element for gaining understanding of the complex array of climate factors that modulate hurricane activity.
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