Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth
Dynamic behaviour of the East Antarctic ice sheet during Pliocene warmth
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DOI：
10.1038/ngeo1889
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发表时间：
2013-09-01
影响因子：
18.3
通讯作者：
Brinkhuis, Henk
中科院分区：
文献类型：
--
作者：
Cook, Carys P.;van de Flierdt, Tina;Brinkhuis, Henk
上新世（533 - 258万年前）温暖时期的特征是全球温度与本世纪末的预测相当（1），大气CO2浓度与今天相似（2-4）。对这些时期全球海平面最高点的估计（5）意味着东南极冰盖可能会退缩，但来自南极边缘的近冰证据很少。在这里，我们提出了新的数据从上新世海洋沉积物中恢复近海的阿德利地，东南极洲，揭示了动态行为的东南极冰盖附近的低洼威尔克斯冰下盆地在过去的气候温暖的时候。530万至330万年前沉积的沉积序列表明，南大洋表层水生产力增加，与环南极温度升高有关。在这些温暖的时间段沉积的碎屑物质的地球化学来源表明，大陆基岩从威尔克斯冰下盆地，今天埋在东南极冰盖下的区域内的积极侵蚀。我们解释这种侵蚀与冰盖边缘后退数百公里的内陆，并得出结论，东南极冰盖是敏感的气候变暖在上新世。
Warm intervals within the Pliocene epoch (5.33-2.58 million years ago) were characterized by global temperatures comparable to those predicted for the end of this century(1) and atmospheric CO2 concentrations similar to today(2-4). Estimates for global sea level highstands during these times(5) imply possible retreat of the East Antarctic ice sheet, but ice-proximal evidence from the Antarctic margin is scarce. Here we present new data from Pliocene marine sediments recovered offshore of Adelie Land, East Antarctica, that reveal dynamic behaviour of the East Antarctic ice sheet in the vicinity of the low-lying Wilkes Subglacial Basin during times of past climatic warmth. Sedimentary sequences deposited between 5.3 and 3.3 million years ago indicate increases in Southern Ocean surface water productivity, associated with elevated circum-Antarctic temperatures. The geochemical provenance of detrital material deposited during these warm intervals suggests active erosion of continental bedrock from within the Wilkes Subglacial Basin, an area today buried beneath the East Antarctic ice sheet. We interpret this erosion to be associated with retreat of the ice sheet margin several hundreds of kilometres inland and conclude that the East Antarctic ice sheet was sensitive to climatic warmth during the Pliocene.