Late Quaternary environment of southern Windmill Islands, EastAntarctica

[摘要] Analyses on a sediment core collected from the Windmill Islands, East Antarctica are used todemonstrate that climatic conditions in this region prior to the Last Glacial Maximum were similar to thoseduring the Holocene and that the area was overrun by ice at some stage between 26 kyr BP and the onset ofbiogenic sedimentation 11 kyr BP. The 10.9 m long core was taken from a marine inlet (epishelf lake) onPeterson Island and is predominantly a sapropel of Holocene age. Material in the lower part of the coreincludes a till layer lain down during the last glacial in the region and below this till is material which hasbeen dated to 26 kyr BP. Geochemical analyses conducted on the core demonstrate similarities between theHolocene sequence and the preglacial material. The Holocene sequence shows enhanced biogenicproduction and periods of open water around 4 kyr BP, suggesting a climatic optimum around that time. Asubsequent decline in conditions, probably a colder climate with greater extent of sea ice, is evident from1 kyr BP to the present. The data support results from ice core studies on nearby Law Dome, which suggestthere was a period of warming around 11.5 to 9 kyr BP, that recent summer temperatures are low relative to afew centuries ago, and that increasing winter temperatures are the main contributing factor to a recent overallwarming in the region.

[学科分类] 自然科学（综合）