Flow and internal structure of a rock glacier
Flow and internal structure of a rock glacier
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岩石冰川的流动和内部结构
DOI：
10.3189/s002214300000318x
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发表时间：
1997
影响因子：
3.4
通讯作者：
E. Lachapelle
中科院分区：
文献类型：
--
作者：
Roger Elconin;E. Lachapelle
阿拉斯加Wrangell山脉Fireweed岩石冰川末端的完整横截面暴露出一层薄薄的未固结碎片覆盖在冰和岩石的固结范围内。主要的岩石冰川由三条支流补给；在末端，三者之间的接触是明确的。含冰量按体积计为50%。冰基质的气泡叶理和晶体形态与报道的冰川冰相似。富冰褶皱地层和透镜体、片理面、板状冰封碎屑的长-中间轴面向岩石冰川中心线沉睡倾斜。平面结构通常与含有干流的陡峭峡谷壁平行。这些陡峭倾斜的纵向构造似乎是由横向压缩造成的，在那里支流汇合，干流向下变窄。在中部和西部支流的顶端，贝格施隆德状和摩陵状的特征分别暴露出与末端相似的混合冰和岩石，但缺乏发育良好的流动结构。不稳定的环状冰顶形成的冰体和多成因冰均在顶底积聚，并为支流岩石冰川提供营养。
Abstract Exposure of a full transverse cross-section of the terminus of Fireweed rock glacier, Wrangell Mountains, Alaska, revealed a thin layer of unconsolidated debris mantling a consolidated mélange of ice and rock. The main rock glacier is fed by three tributaries; at the terminus, contacts between the three are sharply defined. Ice content is >50% by volume. Bubble foliation and crystal morphologies of the ice matrix are similar to those reported from glacier ice. Folded ice-rich strata and lenses, foliation planes, and the long-intermediate axial planes of tabular-shaped englacial clasts dip sleeply toward the center line of the rock glacier. The planar structures generally parallel the steep walls of the gorge containing the trunk stream. These steeply dipping, longitudinal structures appear to result from transverse compression where the tributaries converge and the trunk stream narrows down-valley. Bergschrund-like and moulin-like features at the heads of the middle and west tributaries, respectively, exposed admixed ice and rock similar to that of the terminus but lacking the well-developed flow texture. Talus from the unstable cirque headwall and polygenetic ice both accumulate at the base of the headwall and nourish the tributary rock glaciers.