摘要
大王山剪切带内出现一系列规模不等的糜棱岩条带,广泛发育S面理和C面理,还出现一系列次级拉伸折劈理、剪切条带和不对称小褶纹。剪切带中的石英、云母等基质矿物以塑性变形为主,出现动态重结晶、亚晶、波状消光等显微构造。长石主要以破裂和香肠化为主,出现粒内的张裂隙和肿缩构造。石英和长石存在明显的流变学差异。通过构造和显微构造特征判定,大王山剪切带为右旋剪切带。吴川-四会断裂曾经历过右旋韧性剪切作用。
A series of mylonite bands, S-cleavages, C-cleavages, secondary ex-tensional crenulation cleavages, shear bands and minor asymmetric foldsare developed in the Dawangshan shear zone where quartz, mica andother matrix minerals mainly suffered plastic deformation and micro-structures such as dynamic recrystallization. subgrain, wave extinctionetc. were formed. Feldspar mainly experienced brittle deformation. Frac-tures, boudinages, pinch-and-swell structures etc. were formed. It isobvious that there was flow difference between quartz and feldspar.Observed and measured structures and microstructures suggest thatthe Dawangshan shear zone is a dextral or clockwise and the Wuchuan-Sihui fault zone underwent dextral ductile deformation.
