河南夏馆—二郎坪一带叠加改造型金矿床地质特征及成矿模式

Geological features and metallogenic model of hydrothermal superimposion (regeneration) gold deposits from Xiaguan to Erlangping in Henan

河南内乡夏馆—西峡二郎坪一带金矿床(点)广泛分布,成矿类型多样,产出条件复杂,岩体与围岩接触带以及中元古代和早古生代地层中都有金矿形成。根据成矿物质、成矿流体来源和成矿机制,将产于接触带和地层中的金矿体分为5种类型,它们是在火山、火山沉积和正常沉积等不同背景下,由岩浆热液、变质热液或地下水热液叠加改造(再造)形成的,每类矿床都经历了多期多阶段成矿过程,以后期热液交代、充填成矿为主。构造对金矿形成有明显控制作用,区域性深大断裂控制金成矿带,二级韧脆性剪切带控制金矿床分布,三级层间破碎带、断裂裂隙带和接触带构造控制矿体就位。构造热液的叠加改造或再造主导了成矿作用。

From Xiaguan to Erlangping in Henan gold deposits (mineralized pits) occur extensively; they vary in mineralization type and their conditions of occurrence are complex. Gold deposits formed in intrusive bodies and contact zone between intrusive bodies and wall rocks, and in Mesoproterozoic and early Palaeozoic strata. The authors divide gold deposits in contact zones and strata into five types on the basis of ore source, metallogenic fluid origin and mineralization mechanism. The gold deposits are formed because of magma hydrothermalism, metamorphic hydrothermalism and hydrothermal superimposion on the background of volcanism, volcanic sedimentation and normal sedimentation. Each type of gold deposits is experienced multiphase and polystage mineralization, but mainly late hydrothermal replacement and packing mineralization. Tectonics controls the formation of gold deposits distinctly. The regional deep fault belt controls gold deposits belt. Second-order ductile-brittle shear belt controls the distribution of gold deposits; three-order tectonics of interlayer fractured zones, fracture crack zones and contact zones control the ore forming. In all, the main mineralization was hydrothermal superimposion or regeneration.