| Summary: | Piston cores and single-channel seismic data were acquired in Marguerite Bay, Antarctic Peninsula, to determine modern sedimentary conditions and recent glacial history of the area. Seismic data in the bay shows a rugged seafloor, having numerous deep troughs and a marked lack of sediment cover, with a thin layer of sediment over crystalline basement or older glacial deposits. Modern sedimentation consists predominantly of diatomaceous muds; ice-rafted debris is unimportant. These sediments show wind-driven or marine current influence. Piston cores are topped by diatomaceous muds, which are underlain by terrigenous muds and muddy gravels that were deposited beneath an ice shelf. Basal till sediments were recovered, reflecting deposition by a grounded marine ice sheet. A reconstruction of the glacial history of Marguerite Bay since the last glacial maximum shows grounded ice filling the bay in late Wisconsin time; rising sea level caused slow ice margin retreat and existence of an ice shelf throughout the Holocene. An ice margin recessional facies model has been developed.
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