Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet
Ancient pre-glacial erosion surfaces preserved beneath the West Antarctic Ice Sheet
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DOI：
10.5194/esurf-3-139-2015
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发表时间：
2014-07
期刊：
影响因子：
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通讯作者：
K. Rose;N. Ross;T. Jordan;R. Bingham;H. Corr;F. Ferraccioli;A. L. Brocq;D. Rippin;M. Siegert
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文献类型：
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作者：
K. Rose;N. Ross;T. Jordan;R. Bingham;H. Corr;F. Ferraccioli;A. L. Brocq;D. Rippin;M. Siegert
抽象的。我们提出了冰穿透雷达证据古老的（冰前）和广泛的侵蚀面保存在上游研究所和莫勒冰流，南极洲西部。雷达数据显示一个平滑、横向连续、坡度平缓的地形块体，由两个表面组成，两个表面被一个明显的坡度突变所分隔。由于Pirrit和Martin-Nash山丘对冰盖流动的集体作用，侵蚀面在该位置得以保留，导致这些主要地形障碍下游形成一个缓慢流动的冷基冰区域。我们的分析表明，平滑，平坦的冰下地形并不总是对应于区域的现在或以前的快速冰流，如先前所假设的。我们讨论了侵蚀面的潜在来源。目前地表的侵蚀率很低，排除了通过现代冰川侵蚀形成的可能性。我们认为，河流或海洋的过程是最有可能导致这些表面的形成，但我们承认，这些过程之间的确定性区分需要进一步的数据。
Abstract. We present ice-penetrating radar evidence for ancient (pre-glacial) and extensive erosion surfaces preserved beneath the upstream Institute and Moller ice streams, West Antarctica. Radar data reveal a smooth, laterally continuous, gently sloping topographic block, comprising two surfaces separated by a distinct break in slope. The erosion surfaces are preserved in this location due to the collective action of the Pirrit and Martin–Nash hills on ice sheet flow, resulting in a region of slow flowing, cold-based ice downstream of these major topographic barriers. Our analysis reveals that smooth, flat subglacial topography does not always correspond to regions of either present or former fast ice flow, as has previously been assumed. We discuss the potential origins of the erosion surfaces. Erosion rates across the surfaces are currently low, precluding formation via present-day glacial erosion. We suggest that fluvial or marine processes are most likely to have resulted in the formation of these surfaces, but we acknowledge that distinguishing between these processes with certainty requires further data.