Paleotempestological
Research in South Carolina
Paleotempestological
Research in South Carolina
Paleotempestological investigations utilize the sedimentary record of coastal environments to determine the frequency of prehistoric hurricanes from preserved overwash events from intense hurricane landfalls. . To date, only one paleotempestological study has been conducted in South Carolina salt marshes (Collins, et al., 1998). This study relied primarily on the presence or absence of displaced foraminifera as the prime indicator of hurricane events.
The objectives of this research include 1) calibration of sedimentological evidence of hurricane landfalls with a 300 year record of hurricane landfalls on the South Carolina coastline (Mock, 2004) and 2) improvement of paleotempestological investigations by introducing a computer-based micro-structural approach to resolve the extent of coastal flooding due to intense hurricane events. To achieve these objectives multidisciplinary analyses were performed on cores extracted from a carefully selected coastal pond, Middleton pond, in Georgetown County, SC. The cores were digitally photographed and described, then subjected to magnetic susceptibility, bulk density,210Pb analysis and CHN ratios. Magnetic susceptibility profiles provide clues to lithological signals and stratigraphic correlation. Bulk density data were used to determine porosity for the 210Pb profiles and sedimentation rate estimates within the cores. C/N ratios are used to provide an idea of paleoenvironmental changes and more clues to lithology and stratigraphy.
For the computer-based analyses of the micro-structural sedimentary fabric, thin-walled aluminum boxes (dimensions 15x3x0.5 cm) were used to take undisturbed soft sediment samples from selected intervals of the core face. These flat sub-cores are in the process of being thin-sectioned after being impregnated with epoxy and freeze-dried using the methodology developed by Pierre Francus(1997) and based on Von Merkt (1971). Special software made available to us by Francus will be used to perform computer-assisted examinations of the composition and sedimentary micro-structures of the sub-cores. The back-scattered electron (BSE) images will provide quantitative data of size, shape, orientation and packing of the grains forming the sedimentary structures (Francus and Karabanov, 2000).