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Seven subenvironments of a coastal Georgia Holocene salt marsh vary conspicuously in grass types and topography. However, preliminary examination has revealed few basic differences in sedimentary structures and grain-size distribution of the sediments, from these various parts of the marsh. Samples from these subenvironments are classed as either clays or silty clays, and any primary sedimentary structures in these habitats have been reworked biogenically by burrowing organisms and/or disturbed by plant activity. Noticeable variations do occur in subenvironments in which silt and sand predominate over clay-size materials. Tidal creek banks show laminations, crossbedding, slump structures, and filled-in burrows. Levees bordering major drainage tributaries and barrens adjac nt to the Pleistocene barrier island show no distinct structures but have a distinctive grain-size distribution in the silty sand to fine-grained sand range. Minerals present include quartz, feldspar, montmorillonite, kaolinite, chlorite, and illite at all sampled stations, with only slight variation in relative proportions.
The widespread uniformity of the normal marsh and the grain-size variation on and adjacent to tidal levees suggest that the topography and grass types delimiting subenvironments are controlled chiefly by the tidal and freshwater hydrography of the marsh.
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