Featured Science Paper
Rapid deglaciation of Marguerite Bay, western Antarctic Peninsula in the Early Holocene
This paper reports new glacial geological data that provide evidence for the timing of ice-sheet retreat and thinning at the end of the last glaciation (~10,000 years ago) in Marguerite Bay, on the west coast of the Antarctic Peninsula. We have dated both the length of time rock outcrops have been exposed, which allow us to date the thinning of the ice sheet, and the record from seabed sediments, which allows us to determine how the ice sheet retreated across the continental shelf. The dating shows a surprising pattern. About 9,600 years ago, the ice in Marguerite Bay appears to have thinned very quickly indeed, an observation that turns out to be consistent with several other datasets from the same area (ice-shelf collapse histories, raised beaches and lake sediment cores).
Further north, around Vernadsky Station, the ice-sheet retreat was much more gradual. Thus the rapid retreat of ice in Marguerite Bay was rather localised, and probably driven by specific local conditions. Indeed, there is some evidence that the retreat occurred at a time when warmer water was present on the continental shelf, leading us to suggest that the Marguerite Bay ice stream may have been destabilised, at least in part, by changes in the ocean. This finding supports recent observations that suggest a strong oceanic influence on ice-sheet change, and has implications for future stability of other parts of the Antarctic ice sheet.
M.J. Bentley, J.S. Johnson, D.A. Hodgson, T. Dunai, S.P.H.T. Freeman, C. O. Cofaigh
Quaternary Science Reviews 30 (2011) 3338e3349