陕西八卦庙特大型金矿床成矿机理

Mechanism of Baguamiao large gold deposit,Shaanxi

通过对成矿地质背景、成矿物质来源、成矿物质运移方式和成矿富集条件的综合研究 ,认为八卦庙金矿床的成矿物质来源于下地壳 (太古代 )结晶基底。主要成矿期和成矿方式为 :晚泥盆世发育在秦岭微板块伸展背景下与同生断裂伴生的海底热水喷流活动 ,在热水沉积洼地沉积的热水混合浊积岩相是矿区的含矿建造 ;华力西—印支期矿区发育的脆—韧性剪切作用控制着金的成矿过程并形成金矿体的主体 ;燕山期陆内运动形成的岩浆气液对金矿的再次叠加富集最终形成金矿床 ;因而具有多期次复合成矿的特点。与成矿期和成矿方式相对应 ,其成矿富集条件为 :晚泥盆世三级热水沉积盆地中的次级裂陷槽 ;脆—韧性剪切带中的构造岩和构造扩容空间 ;NE相节理石英脉。八卦庙金矿可能是地幔柱或热点一个长期活动的结果。

Based on multidisciplinary analysis and studies of mineralizational background, material source, removal ways and gold enriching factors, the paper states the mineralizational mechanism of Baguamiao gold deposit The conclusions are drawn out Mineralizational material comes from lower crust or Archaean crystalline basement There are three mineralizational ways First, the bathymetric turbidity facies fine clastic rock of Upper Devonian, which was formed in extensional basement and related to contemporaneous faults and mantle plume action, is mineral formation, as submarine hot spring production Second, the brittle-ductile shearing controls mineralizing process and forms main gold bodies in main M D Finally, gold is enriched again by juvenile gas-fuild from mantle in Yenshanite movement Baguamiao large gold deposit mightresult from a long term movement of mantle plume or hot plots