Converging flow and anisotropy cause large-scale folding in Greenland's ice sheet.
Converging flow and anisotropy cause large-scale folding in Greenland's ice sheet.
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DOI：
10.1038/ncomms11427
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发表时间：
2016-04-29
影响因子：
16.6
通讯作者：
Weikusat I
中科院分区：
文献类型：
--
作者：
Bons PD;Jansen D;Mundel F;Bauer CC;Binder T;Eisen O;Jessell MW;Llorens MG;Steinbach F;Steinhage D;Weikusat I
越来越多的高质量的冰穿透雷达数据目录提供了一个独特的洞察格陵兰冰盖的内部分层结构。地层学是过去变形的一个指标，突出了冰流的不规则性，并揭示了与基岩形状没有明显联系的大扰动。在这项工作中，建立一个新的概念模型的形成过程中，我们分析了雷达数据在彼得曼冰川，北格陵兰岛的发病，并创建了一个三维模型的几个不同的地层。我们证明，占主导地位的结构是圆柱形褶皱子平行于冰流。通过数值模拟，我们表明，这些褶皱可以形成的机械各向异性冰的横向压缩，而层之间的一般粘度对比不会导致折叠相同的边界条件。我们的结论是，褶皱主要是由会聚流形成的机械各向异性冰被引导到冰川。 人们提出了一系列极地冰盖大规模折叠的机制。在这里，使用新的三维重建这样的褶皱在格陵兰彼得曼冰川的起始区域，作者表明，这些形成由于流动收敛和冰的高机械各向异性。
The increasing catalogue of high-quality ice-penetrating radar data provides a unique insight in the internal layering architecture of the Greenland ice sheet. The stratigraphy, an indicator of past deformation, highlights irregularities in ice flow and reveals large perturbations without obvious links to bedrock shape. In this work, to establish a new conceptual model for the formation process, we analysed the radar data at the onset of the Petermann Glacier, North Greenland, and created a three-dimensional model of several distinct stratigraphic layers. We demonstrate that the dominant structures are cylindrical folds sub-parallel to the ice flow. By numerical modelling, we show that these folds can be formed by lateral compression of mechanically anisotropic ice, while a general viscosity contrast between layers would not lead to folding for the same boundary conditions. We conclude that the folds primarily form by converging flow as the mechanically anisotropic ice is channelled towards the glacier. A range of mechanisms has been proposed for large-scale folding in polar ice sheets. Here, using new three-dimensional reconstructions of such folds in the onset region of the Greenland Petermann Glacier, the authors show that these formed due to flow convergence and the high mechanical anisotropy of ice.