A Distant Hurricane Isaac (2012) Exposes Humicrete Along a Portion of Seagrove Beach, Florida, U.S.A.

摘要

Hurricanes and tropical storms can generate storm surges and storm waves that adversely affect distant coastlines. Hurricane Isaac passed approximately 322 kilometers southwest of Seagrove Beach, Florida, on August 28, 2012. From that distance, Isaac's storm surge and waves removed quartz sand from the shoreline, eroded and flattened the renourished beach, and swashed up to the base of the backshore dune, exposing several areas of underlying humate-cemented sand (i.e., humicrete). Three slightly compositionally dissimilar forms of humicrete were identified suggesting a complex development caused by changes in groundwater geochemistry, geohydrology, and geomorphology since the Late Pleistocene. Within a few months following the hurricane, many of these humicrete exposures were covered by quartz sand both by natural and manmade processes. Although beach renourishment in Florida plays a vital role in tourism revenue, it can remove important coastal geological exposures such as these humicretes from direct study.