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 BP (6 ka). Stable-isotope (tSD) 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 tSD. 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 <5D 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 at about 6 ka, co­incident with the environmental changes inferred from the sediment and ice-core records. T he similarity in timing suggests an important role for climate in controlling the evolu­tion of ice-shelf margins following the end of the last glaciation.