Department of Earth System Science

Evidence from the Ross embayment, Antarctica, suggests an abrupt cooling and a concomitant increase in sea-ice cover at about 6000 sp (6 ka). Stable-isotope (delta D) concentrations in the Taylor Dome ice core, at the western edge of the Ross embayment, decline rapidly after 6 ka, and continue to decline through the late Holocene. Methanesulfonic acid concentrations at Taylor Dome show opposite trends to delta D. Sediment cores from the western Ross Sea show a percentage minimum for the sea-ice diatom Fragilariopsis curta between 9 and 6 ka, when Taylor Dome delta D values are highest, followed by an increase through the late Holocene. Radiocarbon dates from raised beach deposits indicate that the retreat of ice shelves in the Ross embayment ceased atabout 6 ka, coincident with the environmental changes inferred from the sediment and ice-core records. The similarity in timing suggests an Important role for climate in controlling the evolution of ice-shelf margins following the end of the last 9 glaciation.