The geomorphological record of an ice stream to ice shelf transition in Northeast Greenland
The geomorphological record of an ice stream to ice shelf transition in Northeast Greenland
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格陵兰岛东北部冰流到冰架过渡的地貌记录
DOI：
10.1002/esp.5552
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发表时间：
2023
影响因子：
3.3
通讯作者：
Lane T
中科院分区：
文献类型：
--
作者：
Lane T
了解冰流动力学在十年到千年的时间尺度是至关重要的，以改善冰盖的行为和未来的冰损失的数值模型预测。在海洋终端设置，冰架在控制冰流接地线稳定性和冰通量到海洋中发挥着关键作用，但很少有研究调查冰架在冰川消退期间的陆地横向地貌印记。在这里，我们记录的陆地冰消陆系统的Nioghalvfjerdsfjorden冰川（79 N）在格陵兰岛东北部，继末次冰期最大，和边缘的横向过渡到一个浮冰架。高海拔地区受到当地冰盖的影响，并显示出本地到异地的块场，标志着当地冰盖与下方冰流的相互作用。从冷基到暖基冰的热转变由不规则体在异地块体上的就位表示。低于海拔600米（a.s.l.）冰川磨损的基岩表面和侧冰碛、“丘状”冰碛、凹槽地形和冰接触三角洲的组合记录了以前存在的暖基冰和随时间推移变薄的接地冰流边缘。在外峡湾的一系列地貌，如冰架冰碛、死冰地形和冰缘冰水沉积是由冰架在冰消期间产生的。沿着中峡湾和内峡湾区域，没有这种冰架信号，这表明在潮汐条件下，在接地线后退之前，冰架已经解体。然而，在海洋界限以下，沿着峡湾的地貌记录表明，在新冰期期间，79 N冰架的扩张在小冰期达到顶峰。随后是世纪的衰退，形成了一系列压缩性冰架冰碛、冰缘河冰走廊、冰碛阶地、死冰地形和裂缝填充脊。这些标志着冰架迅速变薄，并代表了当今气候变暖下的冰架陆地系统。
Understanding ice stream dynamics over decadal to millennial timescales is crucial for improving numerical model projections of ice sheet behaviour and future ice loss. In marine‐terminating settings, ice shelves play a critical role in controlling ice‐stream grounding line stability and ice flux to the ocean, but few studies have investigated the terrestrial lateral geomorphological imprint of ice shelves during deglaciation. Here, we document the terrestrial deglacial landsystem of Nioghalvfjerdsfjorden Glacier (79N) in northeast Greenland, following the Last Glacial Maximum, and the margin's lateral transition to a floating ice shelf. High‐elevation areas are influenced by local ice caps and display autochthonous to allochthonous blockfields that mark the interaction of local ice caps with the ice stream below. A thermal transition from cold‐ to warm‐based ice is denoted by the emplacement of erratics onto allochthonous blockfields. Below ~600 m above sea level (a.s.l.) glacially abraded bedrock surfaces and assemblages of lateral moraines, ‘hummocky’ moraine, fluted terrain, and ice‐contact deltas record the former presence of warm‐based ice and thinning of the grounded ice stream margin through time. In the outer fjord a range of landforms such as ice shelf moraines, dead‐ice topography, and ice marginal glaciofluvial outwash was produced by an ice shelf during deglaciation. Along the mid‐ and inner‐fjord areas this ice shelf signal is absent, suggesting ice shelf disintegration prior to grounding line retreat under tidewater conditions. However, below the marine limit, the geomorphological record along the fjord indicates the expansion of the 79N ice shelf during the Neoglacial, which culminated in the Little Ice Age. This was followed by 20th century recession, with the development of a suite of compressional ice shelf moraines, ice‐marginal fluvioglacial corridors, kame terraces, dead‐ice terrain, and crevasse infill ridges. These mark rapid ice shelf thinning and typify the present‐day ice shelf landsystem in a warming climate.
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影响因子：
56.9
作者：
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通讯作者：
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影响因子：
4
作者：
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通讯作者：
Dorschel, Boris
DOI：
--
发表时间：
2007
期刊：
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作者：
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DOI：
--
发表时间：
2015
期刊：
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作者：
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DOI：
--
发表时间：
2016
期刊：
影响因子：
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作者：
D. Evans;R. Storrar;B. Rea
通讯作者：
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