一条特殊的超浅成脆-韧性剪切带:湘西白沙镇含油瘤状灰岩带

A Peculiar Super Hypabyssal Brittle ductile Shear Zone: Baisha Oil bearing Nodular Limestone Zone, Western Hunan

湘西泸阳县白沙镇西发育了一条特殊的脆韧性剪切带。该剪切带中除了发育了许多脆性变形外，还发育了许多韧性剪切的标志：如Ｓ－Ｃ组构，方解石鱼、核幔构造、方解石ｅ双晶、方解石波状消光、钙质糜棱岩条带以及（光学）各向异性体。经研究发现该剪切带的形成深度不超过３．０ｋｍ，其中的大量石油也与脆韧性剪切作用有一定关系。

A special brittle ductile shear zone crops out in the Baisha town of Luyan county,western Hunan.In this shear zone,apart from many brittle deformations,a great number of brittle ductile shear marks such as S C fabrics,calcite fish,core mantle structure, calcite e twin, calcite wavy extinction, calcareous mylonite belt and optical anisotropic bitumenite,have been developed.The study indicates that the shear zone was formed at less than 3 0 kilometers depth.A great deal of oil in the shear zone is considered to be related to shearing.