GRAIN SIZE VARIATIONS IN DEVELOPED AND UNDEVELOPED MARSH CORES FROM THE GEORGIA COAST

This study investigates the sediments in 50 cm long push cores taken from marshlands surrounding Skidaway Island, located near Savannah, Georgia. Push cores were taken from moderately developed and undeveloped parts of the Skidaway Island marsh and were subsequently subsampled at 2 cm intervals for sedimentological analysis. The sedimentological portion of the study set out to describe the spatial and temporal distribution of sediment grain size. A textural difference is apparent between the low and high marsh cores. Overall, greater than 90% of the sediments from the low marsh samples is fine grained (<63 mm). Greater than 50% of the sediment from the high marsh samples is coarse grained (>63 mm).

Grain sizes from Low Marsh Core 1 (undeveloped) and Low Marsh Core 2 (developed) range from 7F (fine silt) to 11F (clay), with very fine silt dominant. The finest sediments are concentrated near the top and base of the core. Grain sizes from the fine fraction of the High Marsh Core 1 (undeveloped) range from 6F (medium silt) to 9F (clay), with fine silt and very fine silt dominating As with the low marsh cores, the finest sediment is concentrated near the top and base of the core. Coarse fraction sizes range from 1F (medium sand) to 3F (fine sand), with the mean equaling 2.5F (fine sand). Grain sizes from the fine fraction of High Marsh (developed) Core 2 range from 8F (very fine silt) to 10F (clay), with very fine silt dominating. Coarse fraction sizes range from 2-3F (fine sand), with the mean equaling 2.8F (fine sand).