四川呷村VMS多金属矿床的区域变质变形改造——露头和显微构造的观察

Regional Metamorphism on the Ores in Gacun VMS Deposit,Western Sichuan,China:Observation on the Cropout and Microstructure

四川呷村富银多金属矿床是一个晚三叠世形成的块状硫化物(VMS)矿床,后又经历了绿片岩相条件下的区域变质变形作用改造。野外研究和室内组构观察表明,该矿床出露的似层状矿化体形状是区域构造"重构"的结果;不同硫化物的不同变形习性,构成了脆性—塑性变形组构共存的复杂样式,矿石的条纹和条带状构造主要是"软"硫化物矿物塑性变形引起的机械再活化作用的结果。各矿化体目前的产状和空间关系主要受后期构造变形控制,矿化体的初始空间展布需要甄别和恢复。

Gacun polymetallic deposit, a typical VMS deposit, was subjected to greenschist facies regional metamorphism and related deformation after Indo-Chinese epoch. The results of detailed field and microscopic studies on the deposit show that the stratiform orebodies underwent extensive structural reformation and that the distinct deformed behaviours from different sulfides gave rise to the complex style with both brittle and plastic deformed fabrics. The streaky and banded structures in the ores were resulted from the remobilization of solid-state mechanical transfer in plastic deformation of ＂soft＂ sulfides. Because the present occurrences of the bodies are controlled by late-stage structural activities, they can＇t directly represent the original locations and occurrences of orebodies in the VMS deposits.