Crystal Fabric Studies on Emmons Glacier Mount Rainier, Washington
Crystal Fabric Studies on Emmons Glacier Mount Rainier, Washington
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华盛顿州雷尼尔山埃蒙斯冰川的水晶织物研究
DOI：
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发表时间：
1951
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影响因子：
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通讯作者：
G. P. Rigsby
中科院分区：
文献类型：
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作者：
G. P. Rigsby
在埃蒙斯冰川的11个地点，利用安装在交叉偏振片之间的6英寸通用载物台，测定了1,725个冰晶的光学取向。晶体直径为0.2-6英寸，每个4½ × 6英寸的薄片中包含3到40个晶体。在四个较高的地点记录了每天3.4-9.2英寸的山谷冰川运动，另外三个地点被认为基本上是停滞的。当绘制在施密特等面积投影上时，大多数位置处的光轴形成一致的图案，其特征在于菱形四边形的拐角处的四个强极大值。在1%的区域中记录的浓度高达26%。菱形四边形的对角的角分离分别平均为84°和52°。静止的冰的模式与移动的冰的模式相同且同样强烈。在所研究的地点，冰川中的极切变面和清晰的冰带落在钻石中心附近。如果这种模式是由冰晶内的滑动控制的，它表明冰晶中的滑动面可能不同于众所周知的基底滑动面。
Optical orientations of 1,725 ice crystals were determined at eleven locations on the Emmons Glacier by means of a 6-inch universal stage mounted between crossed polaroid sheets. The crystals were 0.2–6 inches across and from three to forty were included in each 4½ × 6-inch thin-section. Down-valley glacier movements of 3.4–9.2 inches per day were recorded at four of the higher locations, and another three were in ice believed to be essentially stagnant. The optic axes at most locations, when plotted on a Schmidt equal-area projection, form consistent patterns featuring four strong maxima at the corners of diamond-shaped quadrangles. Concentrations as high as 26 per cent in 1 per cent of the area were recorded. The angular separation of opposite corners of the diamond-shaped quadrangles average 84° and 52°, respectively. The pattern in stagnant ice is the same and as strong as the pattern in moving ice. Poles to shear planes and clear ice bands in the glacier at the locations studied fall near the centers of the diamonds. If this pattern is controlled by gliding within the ice crystals, it suggests the possibility of glide planes in ice crystals other than the well-known basal glide plane.