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Unglaciated coastal areas in East Antarctica provide records of past ice sheet and glacier fluctuations and subsequent environmental conditions. In this paper we review lithological, geochemical, diatom and radiocarbon data from sediment records from inland and epishelf lakes in Bunger Hills, East Antarctica. While some hilltops were unglaciated during the Last Glacial Maximum, till deposits in lake basins indicate infilling by glacier ice prior to the Holocene. Proglacial sedimentation occurred in lakes during the early Holocene. Around 9.6 kabp, deposition of marine sapropel started under relatively warm climate conditions. Inland lakes were affected by high clastic input from meltwater runoff untilc.7.9 kabp, when deposition became highly organic and biogenic proxies indicate a period of cooler conditions. Epishelf lakes experienced a decrease in water exchange with the ocean and increased freshwater input around 7.7 ± 0.2 kabpand after 2.2 kabp. This probably resulted from grounding line advances of the bounding glaciers, which could be either controlled by relative sea level (RSL) lowering and/or climate-driven glacier dynamics. The absence of marine sediments in the postglacial record of Algae Lake indicates that Holocene RSL probably reached a maximum at or below 10 m above present sea level.

Sediment cores around Antarctica provide a unique opportunity to cross check and supplement the climatic information recorded in ice cores. Suitable high-resolution data, however, have not been available until now from East Antarctica. We present results from the longest continuous postglacial marine sediment succession (1290 cm) ever obtained from an East Antarctic basin. Twenty-one radiocarbon dates show a consistent age to depth correlation over the last 9400 calibrated years BP (cal. yr BP). For this time interval distinct changes in the silicified ice-related biotic species assemblages, accumulation rates of organic carbon, £13C values, and C/N ratios were detected. We demonstrate that these sediment signatures can be used as climate proxies. Our results indicate significant Holocene climatic variability with a climatic optimum between 3500 and 2500 cal. yr BP. This was followed by an abrupt and dramatic cooling that took place within less than 200 yr. Corroborating the results of other researchers we hypothesize that this climatic optimum and its termination was a circumantarctic event which would appear to be out of phase with a proposed global temperature trend (maximum) during the Holocene.