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四川省黑牛洞铜矿赋存于中元古代变质火山-沉积岩中,含矿变质火山-沉积岩可能形成于扬子地台西缘大陆被动边缘裂谷带,经历了至少2次韧性变形,变质达到角闪岩相〔泥质原岩:十字石+铁铝榴石(蓝晶石),变基性火山岩:斜长石+普通角闪石+铁铝榴石〕。一方面,经构造动力作用(韧性剪切变形),原矿石经过改造形成韧性剪切带型浸染状矿石或矿化岩(简称剪切型矿石);另一方面,活化、迁移形成的含矿热液在合适的构造部位淀积成块状、准块状、角砾状和浸染状等矿石,形成以块状、准块状和角砾状硫化物为主的铜矿床。剪切型矿石的特征为:①矿石矿物和脉石矿物与围岩片理的产状基本一致,发育大量剪切条带、石英不对称透镜体和石香肠、不协调褶皱;②矿物晶体或集合体一般呈他形、透镜状;在平行片理的面(∥AB面,⊥C)上,矿石矿物集合体呈浸染状、斑点状和薄片状;在垂直片理走向的面(∥AC面,⊥B)上,则呈细条状、透镜状,甚至无根钩状,发育S∧C组构,与围岩变形特征相同;③石英动态重结晶颗粒、对称透镜体、布丁、条带和S∧C组构发育,矿石矿物集合体条带、对称透镜体、无根褶皱,以及与活化、迁移有关的溶蚀结构十分发育。研究结果表明,黑牛洞矿区发育的剪切型矿石和非剪切型矿石是同一构造过程的不同变形阶段,在不同的成矿作用和不同的地球物理化学条件下的产物。
The Heinuodong copper deposit in Sichuan Province occurs in the Mesoproterozoic metamorphic volcano-sedimentary rocks, and the ore-bearing metamorphic volcano-sedimentary rocks may be formed in the passive edge rift zone of the western margin of the Yangtze platform, undergoing at least two ductile deformations and metamorphism Amphibolite facies [argillaceous rock: cross-stone + almandine (kyanite), metamorphic volcanic rocks: plagioclase + common hornblende + almandine〕. On the one hand, after tectonic dynamic deformation (ductile shear deformation), the ore is transformed to form ductile shear zone disseminated ore or mineralized rock (referred to as shear type ore); on the other hand, the ore formed by activation and migration Hydrothermal fluids are deposited as massive, quasi-massive, brecciated and disseminated ores at appropriate structural sites to form copper deposits dominated by massive, quasi-massive and brecciated sulfides. The features of shear-type ores are: ¢ 矿Ore-mineral and gangue minerals are almost the same as those of surrounding rocks, with a large number of shear bands, quartz asymmetric lenticular and sausage, uncoordinated folds; ¢ ò mineral crystals or The aggregates are generally hematic and lenticular in shape. On the parallel surfaces (∥AB plane, ⊥C), the ores of mineral aggregates are disseminated, speckled and flaky; on the surface of the vertically oriented (∥AC Surface and ⊥ B), SAG structures were developed in the form of thin strips, lenticular or even rootless hooks, which were the same as those of the surrounding rock. (3) Quartz dynamic recrystallization grains, symmetric lenticular bodies, puddings and strips And S ∧ C structure development, ore mineral assemblage band, symmetrical lens, rootless folds, and erosion and migration-related structures are well developed. The results show that the shear-type ores and non-shear-type ores developed in the Heiubendong area are different deformation stages of the same tectonic process under different metallogenic processes and different geophysical and chemical conditions.