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美国加利福尼亚州的内华达山脉的爱迪生湖花岗闪长岩中发育了一系列剪切带。作者在研究其中三条剪切带的变形显微构造时,试图用剪切带糜棱岩内的动态重结晶石英粒度及石英残碎斑晶中亚晶粒粒度作为古应力计估算了剪切带形成时的差异应力大小。 采用化学浸蚀法浸蚀剪切带糜棱岩标本的抛光面,浸蚀剂为饱和的氟化氢铵(NH_4HF_2)溶液。浸蚀时间:为揭示重结晶石英颗粒的边界,浸蚀时间为5—7分钟;为揭示石英亚晶粒的边界,浸蚀时间为25—30分钟。然后,在反光显微镜下用交截法测量动态重结晶石英的粒度及石英亚晶粒的粒度(图版Ⅰ)。由三条剪切带6块标本的测量,得到动态重结晶石英粒度平均为20—40μm;亚晶粒粒度平均为8—20μm。
A series of shear zones develop in the Edison Lake granodiorite in the Sierra Nevada, California, USA. When studying the deformation microstructure of three shear bands, the authors attempted to estimate the shear band formation by using the dynamic recrystallization quartz grain size in the shear band mylonites and the subgrain grain size in the quartz residual porphyrite as the ancient stressor When the difference in stress size. The polished surface of the mylonite samples was etched by chemical etching. The etchant was a saturated solution of ammonium hydrogen fluoride (NH 4 HF 2). Etching time: In order to reveal the boundaries of recrystallized quartz particles, the etching time is 5-7 minutes. To reveal the boundaries of quartz subgrains, the etching time is 25-30 minutes. The particle size of the dynamically recrystallized quartz and the grain size of the quartz subgrains were then measured by a cross-cut method under a reflective microscope (panel I). The measurements of six specimens from three shear zones showed that the average particle size of dynamic recrystallized quartz was 20-40μm, and the average grain size of subgrains was 8-20μm.