晋东北隐爆岩及其对金银的控矿意义

CRYPTOEXPLOSIVE ROCK AND ITS ORE FORMING SENSE TO GOLD SILVER DEPOSIT IN THE NORTHEASTERN SHANXI PROVINCE, CHINA

隐爆岩对晋东北次火山岩型金银矿具有重要的控制意义,它是在深源花岗岩浆浅成或超浅成侵入时,由气爆、浆爆和热液注入作用形成的。隐爆角砾岩可分为五种类型,并显示一定的水平和垂直分带性。隐爆岩在相对封闭的系统中形成,因而与火山颈相爆发角砾岩有一系列岩石特征差别,可作为两者区别的标志。由于隐爆岩在花岗岩类岩浆多期次侵入和火山作用的最后阶段形成,因而是含矿热液的最后载体。又由于隐爆岩在相对封闭的空间中形成,且发育多孔多隙的各种角砾岩和次级断裂构造,因而是金银矿床的最佳控矿构造。

Cryptoexplosive rocks have important control senses for subvolcanic rock type gold and silver deposits in the Northeastern Shanxi. They are formed by gas explosion, magmatic explosion and hydrothermal fluid injection when shallow or super shallow intrusion of deep sourced granitic magma took place. Cryptoexplosive breccia rocks can be divided into five types showing more or less horizontal and vertical zoning.Cryptoexplosive rocks are formed in the relative closed system, so there are several differences between cryptoexplosive rocks and explosion breccia of volcanic neck phase and can be taken as distinguishing sign. Cryptoexplosive rocks were formed at final stage of multiple phases of intrusion and volcanism of granitoid magma and therefore become the last carrier of ore bearing magmatic hydrothemal solution. Because cryptoexplosive rocks were formed in relative closed space and contain various porous breceia and subsidiary faulted structure they are best ore control structure of gold silver deposit.