辽宁红透山块状硫化物矿床中矿体的变质变形特征与形成过程

辽宁红透山块状硫化物矿床位于华北克拉通北缘，是中国最大的太古宙块状硫化物矿床。该矿床经历了高级角闪岩相变质变形和后期热液改造。通过野外和矿相学观察，将红透山矿床的主要矿石类型划分为4类。块状矿石呈层状和块状构造，等粒状和变晶结构；粗晶状矿石呈透镜状和块状构造，巨斑状和填隙结构；糜棱岩化矿石又称矿石糜棱岩，矿石呈透镜状和揉皱状构造，细粒化和重结晶结构；富铜矿石，或称"铜条"，呈脉状和板条状，交代残留和乳滴结构，变形显著。通过对以上4类矿石矿物组合、共生关系和变形特征的分析，系统厘定了矿石的成因和形成过程。块状矿石的变形和流体活动不明显，是原生VMS矿石受区域变质重结晶的产物。粗晶状矿石变斑晶发育，黄铜矿和闪锌矿含量极低，代表强烈变质重结晶和再活化后的残余相。矿石糜棱岩韧性变形最强烈，黄铜矿和闪锌矿明显高于块状矿石，代表韧性变形和再活化的硫化物矿石。铜条韧性变形和交代结构发育，以黄铜矿为主，闪锌矿次之，同时含少量指示低温成因的硫铜钴矿，是机械再活化与变质热液再沉淀的产物。

Metamorphic deformation characters and forming process of ore bodies in the Hongtoushan massive sulfide deposit,Northeast China

The Hongtoushan volcanic-hosted massive sulfide(VMS)deposit, located in the northern margin of North China craton, is the largest Archean VMS in China.The main orebodies and host rocks in the deposit have undergone metamorphism and deformation of high amphibolite facies and hydrothermal overprinting.Based on field and mineralogical observation, its main ore types are divided into following four types: a.massive sulfide ores, mainly stratiform and massive in shape, medium-sized, isogranular and crystalloblastic in textures; b.coarse-grained ores, generally lenticular and massive in shape, giant metacryst and interstitial in texture; c.mylonitized sulfide ores, also called ore mylonites, lenticular and crumpled in shape, fine-grained and recrystallized in textures; and d.copper-rich sulfide ores, also called as "copper bar", veined and laminated in shape, metasomatic residual and emulsion textures.Combined with mineral fabric and assemblage, field relationships, and deformation characteristics, the genesis and formation process of the above four types of ores are summarized.The massive sulfide ores are produced by regional metamorphism and recrystallization from primary VMS ores, while ductile deformation and hydrothermal overprinting are unobvious.The coarse-grained ores are dominated by nearly undeformed giant metacrysts with extremely low content of chalcopyrite and sphalerite, representing the residual phase during intensive metamorphic recrystallization and remobilization.Mylonite ores show strongest ductile deformation, with obviously higher contents of chalcopyrite, sphalerite and galena than massive ores, representing extensive ductile deformation and remobilization of massive sulfide ore.Deformation and overprinting structure are developed in copper bars in which sulfide in copper bars is dominated by chalcopyrite, followed by some sphalerite, minor carrollite, and depleted in pyrite or pyrrhotite, indicating mechanical reactivation and metamorphic hydrothermal precipitation under lower temperature.