Sliding and other deformation mechanisms in a glacier of salt, S Iran
Sliding and other deformation mechanisms in a glacier of salt, S Iran
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伊朗南部盐冰川的滑动和其他变形机制
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发表时间：
1981
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通讯作者：
C. Talbot
中科院分区：
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作者：
C. Talbot
总结在伊朗南部的盐冰川之一在这里被解释为一个类似的重力驱动，逆冲推覆复合体已覆盖自己的碎片。从身体的不同部分的组构被解释在晶界扩散和动态重结晶，以及拉伸分离和滑动沿着立方劈裂的碎斑清晰的岩盐。在盐中产生的滑坡就像斜坡一样，盐冰川在那里变慢变厚，以克服基岩的障碍，使其一般的下坡流动。塑性流动褶皱区和较大规模的锯齿状劈理的较小区域形成障碍物的上游，并且载玻片从这些区域的下游端出现。如果有的话，很少有直接斜升到表面，大多数转向盐片内的平面，在那里它们可以作为应力下降退火的结果而愈合。盐质量的能力被假定为减少其长度响应于晶粒尺寸的减小和不溶性晶粒的相对增加。这种能力的下降解释了盐层内部变形特征的变化。首先是滑动，然后是锯齿状劈理未能在连续障碍物的上游发展，最终所有内部折叠停止。相反，盐冰川在最后几个基岩脊上移动，因为调节褶皱和另一种类型的滑动似乎是由层平行滑动形成的。盐冰川中的所有滑坡都起源于其基岩水道的不规则处附近。滑动传播区域保持静止，并且盐在其通过和超过滑动传播区域时撕裂。盐冰川并没有侵蚀它的基岩，而是通过剪切静态盐的填充体，有效地平滑了河道中的不规则性。
Summary One of the salt glaciers in S Iran is interpreted here as an analogue of a gravity-driven, thrust nappe complex which has overridden its own debris. Fabrics from different parts of the body are interpreted in terms of grain boundary diffusion and dynamic recrystallization, together with tensional separation and sliding along the cubic cleavages of porphyroclasts of clear halite. Slides generate within the salt as ramps, where the salt glacier slows and thickens to surmount the bedrock obstructions to its general downslope flow. Zones of plastic flow-folds and smaller zones of large-scale crenulation cleavage form upstream of the obstructions and the slides emerge from the downstream end of such zones. Few, if any, ramp directly to the surface and most turn to flats within the salt sheet where they may heal as a result of stress-drop annealing. The competence of the salt mass is assumed to decrease down its length in response to a decrease in grain size and a relative increase in insoluble grains. Such a decrease in competence accounts for the change in character of the internal deformation of the salt sheet when traced downstream. First the slides and then the crenulation cleavage fail to develop upstream of successive obstructions and eventually all internal folding ceases. Instead, the salt glacier moves over the last few bedrock ridges as accommodation folds and another type of slide appears to form by layer parallel slip. All the slides in the salt glacier originate near irregularities in its bedrock channel. The slide propagation zones remain stationary and the salt tears as it passes through, and beyond them. Instead of eroding its bedrock, the salt glacier effectively smooths irregularities in its channel by shearing over the infilling bodies of static salt.