Major advance of South Georgia glaciers during the Antarctic Cold Reversal following extensive sub-Antarctic glaciation.
Major advance of South Georgia glaciers during the Antarctic Cold Reversal following extensive sub-Antarctic glaciation.
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DOI：
10.1038/ncomms14798
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发表时间：
2017-03-17
影响因子：
16.6
通讯作者：
Bohrmann G
中科院分区：
文献类型：
--
作者：
Graham AG;Kuhn G;Meisel O;Hillenbrand CD;Hodgson DA;Ehrmann W;Wacker L;Wintersteller P;Dos Santos Ferreira C;Römer M;White D;Bohrmann G
南半球副极地岛屿的冰川作用历史尚不清楚。争论围绕着最后一次冰川推进和终止的范围和时间，特别是在亚南极地区的南乔治亚岛。在这里，我们利用海底地球物理数据和海洋沉积岩芯，解析了南乔治亚岛近海从末次盛冰期到全新世过渡期间的冰川作用记录。我们展示了整个大陆架末次冰川推进和渐进冰消作用的海底地貌印记。 c. 峡湾中的冰川重新复苏。 15,170 年前和 13,340 年前恰逢一段更凉爽、更湿润的气候时期，称为南极冷逆转，揭示了冰冻圈对延伸至南大洋大西洋部分的南极气候模式的响应。我们得出的结论是，南乔治亚岛的末次冰期范围很广，并且末次冰期期间冰川对气候变化的敏感性比以前的研究所暗示的更为显着。南乔治亚岛的冰川历史存在争议，许多人认为在末次冰川时期该岛的冰盖出现了沿海限制。在这里，作者展示了这一时期大陆块广泛的冰盖覆盖，以及南极冷逆转期间冰川重新向峡湾口推进的情况。
The history of glaciations on Southern Hemisphere sub-polar islands is unclear. Debate surrounds the extent and timing of the last glacial advance and termination on sub-Antarctic South Georgia in particular. Here, using sea-floor geophysical data and marine sediment cores, we resolve the record of glaciation offshore of South Georgia through the transition from the Last Glacial Maximum to Holocene. We show a sea-bed landform imprint of a shelf-wide last glacial advance and progressive deglaciation. Renewed glacier resurgence in the fjords between c. 15,170 and 13,340 yr ago coincided with a period of cooler, wetter climate known as the Antarctic Cold Reversal, revealing a cryospheric response to an Antarctic climate pattern extending into the Atlantic sector of the Southern Ocean. We conclude that the last glaciation of South Georgia was extensive, and the sensitivity of its glaciers to climate variability during the last termination more significant than implied by previous studies. The glaciated history of South Georgia is debated, with many suggesting a coastal limit to the island's ice cap during the last glaciation. Here, the authors show extensive ice-cap cover of the continental block during this time and a readvance of glaciers to fjord mouths during the Antarctic Cold Reversal.