Abstract
Ross Sea cores contain diatom floras and have sediment characteristics which suggest that grounded ice filled the Ross Sea embayment to the continental shelf margin during the last, and previous, glacial advances. Each successive advance reworked sediments from the previous interglacial period with older material and compressed them into a firm deposit with reworked (mixed and fractured) microfossils. As the grounding line retreated past each core location, subglacial meltwater, tidal pumping, and marine bottom-water flow winnowed light, less heavily silicified diatoms, leaving a lag of Eucampia balaustium in well-sorted, sandy sediment. Warm-water, open-marine conditions initially prevailed after deglaciation on the northern part of the continental shelf during summers. Open-marine conditions were gradually replaced by the pack-ice cover that today characterizes the Ross Sea continental shelf region.
