A SEDIMENTOLOGICAL, GEOCHEMICAL, AND MICROPALEONTOLOGICAL ANALYSIS OF A SKIDAWAY ISLAND (GEORGIA) MARSH

This study will characterize the depositional environment of a salt marsh in Chatham County, Georgia. Cores were taken in a transect across the high marsh of Skidaway Island, Georgia and were subsequently sampled for sedimentological, geochemical, and micropaleontological analyses.  Sedimentological data indicate that both cores are consistently well-sorted down-core.  The dominant mineral in both cores is quartz; phosphate, pyrite, and palynomorphs are also present. A dense layer of blue clay is located at depths starting at 114 cm in core 1 and ~100 cm in core 2 and continues to core refusal.  The clay unit contains mottles, iron concretions and has a low abundance of quartz sand.  A few specimens of planktic and benthic foraminifera are present (mostly in the upper 20 cm of the core while one planktic foraminifera was found 80 cm down-core), consistent with the harsh environmental conditions in the high marsh. Geochemical analyses by complete sample digestion and ICP-MS analysis are presented for three fractions of continuous sample (bulk, <63mm, and <5mm).  These data are compared to data obtained from the analysis of a relatively undeveloped barrier island salt marsh (Sapelo Island, Georgia).  Thus far the data obtained in this study complements data from previous studies of the marsh.  Furthermore, the blue clay layer may indicate a regional structure such as a Carolina bay.