不同层次叠加构造的控矿作用——以内蒙古十八倾壕金矿为例

THE ORE-CONTROL PROCESS OF THE OVER LAP OF STRUCTURE FORMED IN DIFFERENT LEVELS ——An EXAMPLE FROM SHIBAQINGHAO GOLD DEPOSIT,INNER MONGOLIA

十八倾壕金矿控矿构造带是由韧性剪切带、劈理带、反S型构造、张裂和剖面上剪切断裂组成的复杂构造带。这些不同时期、不同性质、不同层次叠加构造,控制了十八倾壕金矿不同矿化期的成矿作用。韧性剪切带形成于晚太古代,它是控矿构造带的原形,形成于地壳深部层次,控制了一条早期金矿化带。劈理带和反S型构造形成于早元古代,是地壳中部层次的产物,其中反S型构造控制蚀变岩型金矿体及富矿部位。构造带张开及部面上的剪切断层形成于地壳浅部层次,前者控制了含金石英脉,后者是对矿床起破坏作用的成矿后构造。

The ore-control tectonic zone of Shibaqinghao gold deposit is complicated consisting of the ductile shear zone,fractured cleavage zone,reversed S-type structures,tension fissures and shear faults. The metallogensis of Shibaqinghao gold deposit in different mineralization periods was controlled by the surperposi tion of structures with different characteristics formed in the different periods and levels. The ductile shear zone formed in the later stage of Archaean era is an embryonic form of the tectonic zone,which was formed in deep level controlling the gold mineralized zone.The fracture cleavage zone and the reversed S-type structures formed in the early stage Proterozonic era belong to the middle level.The reversed S-type structures controlled the ore bodies and distribution of ore shoots of the altered-rock type deposit. The tension fissurs and the shear faults were formed in the shallow crust. The distribution of gold quartz vein was controlled by the former,and the later, post-metallogenic structure was destructive for ore deposits.