Structure and sedimentology of George VI Ice Shelf, Antarctic Peninsula: implications for ice-sheet dynamics and landform development
Structure and sedimentology of George VI Ice Shelf, Antarctic Peninsula: implications for ice-sheet dynamics and landform development
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南极半岛乔治六世冰架的结构和沉积学：对冰盖动力学和地貌发展的影响
DOI：
10.1144/jgs2014-134
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发表时间：
2015
影响因子：
2.7
通讯作者：
Hambrey M
中科院分区：
文献类型：
--
作者：
Hambrey M
南极冰架因气候变暖而崩塌的现象有很多文献记载，但其在沉积地貌方面的影响却鲜为人知。本文利用遥感、构造冰川学和沉积学资料，对该地区的冰川演化进行了评价。南极洲西南部半岛，乔治六世冰架，面积25000平方公里。冰架位于亚历山大岛和帕尔默地之间的南北走向构造裂谷，主要由帕尔默地的冰流滋养。冰架的结构主要是继承叶理和裂缝，并与速度数据表明，在很大程度上压缩流态。冰碛复合体在冰架边缘的形成是由叶理和褶皱中夹带的碎屑控制的。这种冰川碎屑是基础的起源，包括当地中生代沉积和火山岩性，和外来的结晶岩石帕尔默土地。在帕尔默地的冰川源中，基底冰折叠到一个很高的水平是将碎片带到表面所必需的。这些结果对于理解压缩流下冰架的流动动力学、碎屑夹带和与古冰架相关的冰碛形成具有意义。补充资料冰架形态、冰相和冰结构的照片;冰相的详细描述，包括叶理记录，解释沉积相的支持证据;沉积学数据的完整数据集，包括碎屑形状的三角形图、碎屑圆度直方图、砂粒度及以下粒度的粒度分布，以及帕尔默地本地碎屑与外来碎屑的饼图;和一个表格，根据薄片分析，总结了冰架冰碛中代表性碎屑的特征，并指出了它们的来源，可在www.example.com上查阅http://www.geolsoc.org.uk/SUP18831
Collapse of Antarctic ice shelves in response to a warming climate is well documented, but its legacy in terms of depositional landforms is little known. This paper uses remote-sensing, structural glaciological and sedimentological data to evaluate the evolution of thec. 25000 km2George VI Ice Shelf, SW Antarctic Peninsula. The ice shelf occupies a north–south-trending tectonic rift between Alexander Island and Palmer Land, and is nourished mainly by ice streams from the latter region. The structure of the ice shelf is dominated by inherited foliation and fractures, and with velocity data indicates a largely compressive flow regime. The formation of a moraine complex at the margin of the ice shelf is controlled by debris entrained within foliation and folds. This englacial debris is of basal origin, and includes both local Mesozoic sedimentary and volcanic lithologies, and exotic crystalline rocks from Palmer Land. Folding of basal ice to a high level in the source glaciers on Palmer Land is required to bring the debris to the surface. These results have implications for understanding flow dynamics of ice shelves under compressive flow, and debris entrainment and moraine formation associated with palaeo-ice shelves.Supplementary materialPhotographs of ice-shelf morphology, ice facies and ice structure; detailed descriptions of ice facies, including foliation logs, supporting evidence for interpreting sedimentary facies; complete dataset of sedimentological data, including triangular plots of clast shape, clast roundness histograms, particle-size distribution of sand-size and lower, and pie chart of local clasts versus exotic clasts from Palmer Land; and a table summarizing the characteristics of representative clasts in the ice-shelf moraine, based on thin-section analysis, with indication of their provenance are available at http://www.geolsoc.org.uk/SUP18831
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