华南加里东期金矿床的基本特征

MAIN CHARACTERISTICS OF CALEDONIAN GOLD DEPOSITS IN SOUTH CHINA

华南加里东期金矿床分布广泛 ,既可产在华南加里东褶皱带内 ,也可发育在毗邻的江南隆起上。其共同特征是矿床产在加里东期构造变形带或变质带中 ,受深大断裂带及其分支构造所控制 ,成矿物质主要来自赋矿围岩。产在隆起上的矿床赋矿围岩时代较老 ,均为元古宙变质细碎屑岩类 ;矿物及元素组合比较简单 ,常见单金型。产于褶皱带中者其围岩除元古宙 -寒武纪变质细碎屑岩外 ,还有火山岩、侵入岩及沉积岩 ,时代为元古宙——志留纪 ;矿物及元素组合比较复杂 ,可见到砷、锑、汞、碲矿物及沥青出现。隆起上的矿床属于加里东期改造作用形成 ,褶皱带中者为改造、受改造及斑岩成矿作用的产物。成矿时代除加里东期外 ,还有燕山期及震旦纪矿化存在。两种构造中的矿床成矿差异主要受物质来源岩石类型。

Gold deposits formed in Caledonian period,the second important gold mineralization period in South China,are widely distributed in South China Caledonian fold belt and adjacent Jiangnan rise.The common characteristics of gold deposits in two tectonic units lie in he development of these deposits in Caledonian tectonically deformed zones or Caledonian metamorphic belts,the control of these deposits by faults in deep fracture zones and their subsidiary fractures,and the derivation of ore\|forming materials from adjacent wall rocks.Gold deposits in the Jiangnan rise are characterized by the existence of these deposits in Proterozoic metamporphosed microclastic rocks and their relatively simple mineral and element associations.Nevertheless,gold deposits in the fold belt occur in Proterozoic\|Silurian volcanic,intrusive and sedimentary rocks as well as Proterozoic\|Cambrian metamorphosed microclastic rocks and consist of rather complex mineral and element associations.Gold deposits in the Jiangnan rise were formed by Caledonian reformation processes and those in the fold belt are products of reformation and porphyry mineralization of Caledonian and,partly,Yanshanian and Sinian periods.Wide distribuion of Caledonian gold deposits is closely related to Caledonian tectonic development in that area.Differences between gold deposits in the Jiangnan rise and those in the fold belt are attributed to the diversity of ore\|forming materials and the superimposed mineralization.