Quantifying subglacial bed roughness in Antarctica: implications for ice-sheet dynamics and history
Quantifying subglacial bed roughness in Antarctica: implications for ice-sheet dynamics and history
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DOI：
10.1016/j.quascirev.2008.10.014
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发表时间：
2009-02
影响因子：
4
通讯作者：
R. Bingham;M. Siegert
中科院分区：
文献类型：
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作者：
R. Bingham;M. Siegert
冰川地貌是由冰流动态机制和冰盖历史形成的复杂地貌组合组成，这些地貌叠加在冰前地形、岩性和地质结构之上，反过来又改变了冰前地形、岩性和地质结构。原则上，通过分析现代冰盖床可以深入了解冰川景观的形成，但现代冰盖下的地形分析受到床的不可接近性的限制。然而，可以量化粗糙度，冰下界面的垂直变化与水平距离，沿着从无线电回波探测（RES）获得的床的二维图像。在这里，我们整理了南极洲的几个案例研究，在那里粗糙度计算已被用作冰川学工具来推断大面积（> 500平方公里）地区的基底过程和冰盖历史。我们提出了两个例子，从西南极洲，这表明床粗糙度在确定冰下沉积物，冰川动力学和前冰盖的大小的存在和范围的效用。我们还提出了两个例子，从东南极洲，这说明了如何粗糙度提供知识的冰盖动力学的内部和前第四纪冰盖的历史。在现代冰盖的设置，表征床粗糙度沿着RES轨道有两个优点是相对简单的计算，同时产生翔实的地下数据，是特别强大的进一步了解时，再加上知识的冰流从外地，卫星和建模调查。该技术还为比较现代和以前的冰盖地形提供了巨大的潜力，有助于更好地了解冰川景观的形成和演变。
Glaciated landscapes consist of complex assemblages of landforms resulting from ice flow dynamic regimes and ice-sheet history, superimposed over, and in turn modifying, preglacial topography, lithology and geological structure. Insights into the formation of glaciated landscapes can, in principle, be obtained by analysing modern ice-sheet beds, but terrain analyses beneath modern ice sheets are restricted by the inaccessibility of the bed. It is, however, possible to quantify roughness, the vertical variation of the subglacial interface with horizontal distance, along two-dimensional images of the bed obtained from radio-echo sounding (RES). Here we collate several case studies from Antarctica, where roughness calculations have been used as a glaciological tool to infer basal processes and ice-sheet history over large (>500km2) areas. We present two examples from West Antarctica, which demonstrate the utility of bed roughness in determining the presence and extent of subglacial sediments, glacial dynamics and former ice-sheet size. We also present two examples from East Antarctica, which illustrate how roughness provides knowledge of ice-sheet dynamics in the interior and pre-Quaternary ice-sheet histories. In modern ice-sheet settings, characterising bed roughness along RES tracks has the twin advantages of being relatively simple to calculate while producing informative subsurface data, and is especially powerful at furthering understanding when coupled with knowledge of ice flow from field, satellite and modelling investigations. The technique also offers significant potential for the comparison of modern and former ice-sheet terrains, contributing to an improved understanding of the formation and evolution of glaciated landscapes.