Fracture geometry of pseudotachylyte generation zones: a study of shear fractures formed during seismic events
Fracture geometry of pseudotachylyte generation zones: a study of shear fractures formed during seismic events
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假速水剂生成区的裂缝几何形状：地震事件期间形成的剪切裂缝的研究
DOI：
10.1016/0191-8141(81)90012-2
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发表时间：
1981
影响因子：
3.1
通讯作者：
J. Grocott
中科院分区：
文献类型：
--
作者：
J. Grocott
描述了西格陵兰伊克托克剪切带发育的假玄武玻璃生成带中剪切裂缝的方向和运动方向，并推断了其破裂序列。生成带发生在强烈的面理化片麻岩中，由一致的，通常成对的，主要的位移剪切断裂（成对剪切），在其上产生大部分熔体，和一个系统的小剪切断裂。小剪切断裂是最激烈的主位移剪切断裂之间，和大多数熔体侵入这些成对的剪切向内相对于该区域。假玄武玻璃岩注入脉的侵入离开主位移剪切断裂，被认为是与生成带的轻微剪切断裂同时发生的。生成带影响完整的岩石，单个主位移剪切断裂的最大位移为4.6 m。成对的主位移剪切断裂相距3米，最大观测长度为1公里。在所描述的所有区域中，断裂似乎是单次滑动的结果。研究区内既有右旋生成带，又有左旋生成带，且几何形态不同。在每一种情况下，位移都是走滑。
The orientation and movement sense of shear fractures in pseudotachylyte generation zones developed in the Ikertôq shear belt, West Greenland are described, and the fracturing sequence is inferred. The generation zones occur in strongly foliated gneisses, and consist of concordant, usually paired, principal displacement shear fractures (paired shears), on which most melt was generated, and a system of minor shear fractures. Minor shear fracturing was most intense between principal displacement shear fractures, and most melt intruded from these paired shears inwards with respect to the zone. Intrusion of injection veins of pseudotachylyte off the principal displacement shear fractures, is believed to be contemporaneous with minor shear fracturing in the generation zones.Generation zones affect intact rocks, and individual principal displacement shear fractures have a maximum displacement of 4.6 m. Paired principal displacement shear fractures are up to 3 m apart, and have a maximum observed length of 1 km. In all the zones described, the fracturing appears to be the result of a single episode of slip. Both dextral and sinistral generation zones occur within the study area, and have different geometries. In each case the displacement is strike-slip.