The last glaciation and deglaciation of the Northeast Greenland continental shelf revealed by hydro-acoustic data
The last glaciation and deglaciation of the Northeast Greenland continental shelf revealed by hydro-acoustic data
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DOI：
10.1016/j.quascirev.2017.01.018
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发表时间：
2017-03-15
影响因子：
4
通讯作者：
Dorschel, Boris
中科院分区：
文献类型：
--
作者：
Arndt, Jan Erik;Jokat, Wilfried;Dorschel, Boris
在北纬76度至北纬80.5度之间的东北格陵兰冰架地区，约有16%的格陵兰冰盖通过海洋终止冰川流失。其中大部分是通过格陵兰岛最大的冰流——东北格陵兰冰流。在冰河时期，冰原延伸到大陆架上，现在的跨大陆架沟槽被冰流填满。在这项研究中，联合调查了三十年研究期间获得的高分辨率水声数据，以揭示过去的冰川条件。我们的数据表明，在末次极大期，西风槽和诺斯克槽被快速流动的冰流填充，这些冰流延伸到陆架边缘。在交叉大陆架槽之间，冰穹位于浅滩上，可能对全球海平面的上升贡献了约1厘米。最有可能的是，这些冰穹在槽间区形成了快速的冰流。在西风槽，末次盛冰期后冰盖向内大陆架的退缩是间歇性的。相比之下，在诺斯克海槽，冰盖退缩相对较快，没有证据表明接地线稳定的阶段。可能在新仙女木时期，冰原在两个冰槽中推进到大陆架的中间位置，这两个冰槽是由接地带楔形记录的。在此期间，挪威海槽形成了厚厚的冰架，释放出扁平的冰山。全新世冰川消融期间，冰原从中陆架向海岸线迅速退缩。(C) 2017 Elsevier Ltd.版权所有。
About 16% of the Greenland Ice Sheet drains in the area of the Northeast Greenland shelf between 76 degrees N and 80.5 degrees N via marine terminating glaciers. Most of it is via the Northeast Greenland Ice Stream, the largest ice stream of Greenland. During ice ages, the ice sheet extended onto the continental shelf and modern-day cross-shelf troughs were filled by ice streams. In this study, high-resolution hydro-acoustic data acquired during three decades of research were jointly investigated to reveal the past glacial conditions. Our data shows that Westwind Trough and Norske Trough were filled by fast flowing ice streams that extended to the shelf edge during the last glacial maximum. In between the cross-shelf troughs, ice domes resided on shallow banks that may have contributed about a decimetre to global sea level. Most probably these ice domes initiated fast ice flow through sinks in the inter-trough area. In Westwind Trough, ice sheet retreat to the inner shelf after the last glacial maximum was intermittent. In contrast, in Norske Trough the ice sheet retreat appears relatively rapid with no evidences for phases of grounding line stabilization. Probably during the Younger Dryas, the ice sheet readvanced to a mid-shelf position in both troughs documented by grounding zone wedges. During this time, a thick ice shelf was present in Norske Trough releasing tabular icebergs. Ice sheet retreat from the mid-shelf to the coastline during Holocene deglaciation was rapid. (C) 2017 Elsevier Ltd. All rights reserved.