Comparison of Modern and Ancient Beaches, Central Georgia Coast: GEOLOGICAL NOTES

Abstract

Although not many ancient beaches have been described from the geologic record, they are environmentally significant and worthy of diligent search. Characteristics of a modern beach at Sapelo Island, Georgia, as seen in section are illustrated and compared with a similar Pleistocene beach 5 mi inland. In general the stratification of the beach conforms to the slope of the beach surface. Individual laminae are thin, parallel, and may be traced for several feet. Departures from parallelism of surface and stratification occur in areas of bar and trough development and near the beach crest. In general, the seaward dip of beach stratification in this area is less than 4 degrees . The upper limit of the diagnostic burrow features made by the marine decapod Callianassa major Say marks the approximate position of mean sea level in both the modern and Pleistocene beaches.