Rapid erosion beneath the Greenland ice sheet
Rapid erosion beneath the Greenland ice sheet
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DOI：
10.1130/g32687.1
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发表时间：
2012-04-01
期刊：
影响因子：
5.8
通讯作者：
Mair, D.
中科院分区：
文献类型：
--
作者：
Cowton, T.;Nienow, P.;Mair, D.
更新世的冰盖留下了明显的侵蚀痕迹，但冰盖侵蚀的速度很难从古地貌或对当代过程的观察中确定。在这里，我们使用两年的沉积物通量数据，来自格陵兰西部出口冰川的融水，计算从冰缘向内陆延伸>50公里的流域的冰下侵蚀的平均速率。该区域的侵蚀速率为4.8 +/- 2.6 mm a（-1），比以前估计的格陵兰冰盖下的侵蚀速率大1-2个数量级。我们的研究结果表明，在表面融水能够访问床，冰盖的侵蚀率是保持在温带高山冰川观察到的快速侵蚀。在冰消期，当融水丰富时，冰盖边缘因此应该充当高效的侵蚀剂。
The Pleistocene ice sheets left a clear signature of erosion, but the rate at which ice sheets erode is difficult to determine from either paleolandscapes or observations of contemporary processes. Here we use two years of sediment flux data, derived from meltwaters emerging from an outlet glacier in west Greenland, to calculate an average rate of subglacial erosion across a catchment extending >50 km inland from the ice margin. Erosion in this zone occurs at 4.8 +/- 2.6 mm a(-1), a rate 1-2 orders of magnitude greater than previous estimates of erosion rate beneath the Greenland Ice Sheet. Our results suggest that where surface meltwaters are able to access the bed, the rate of erosion by ice sheets is in keeping with the rapid erosion observed at temperate alpine glaciers. During deglacial phases, when meltwater was abundant, ice sheet margins should therefore have acted as highly efficient agents of erosion.