黔西南低温成矿域中不同层位不同类型金矿的内在统一成矿机制探讨

The genetic mechanisms of the gold deposits in low-temperature mineralization area in southwestern Guizhou

关键词:  低温成矿域  深大断裂导矿  金矿  黔西南

Key words:  low-temperature mineralization area  deep fault-controlled ore deposit  gold deposit  southwestern Guizhou

摘要:

黔西南地区是扬子地台西南缘重要且极有远景的低温成矿域,以发育金矿为主。其低温是因为该区岩浆岩露头极少,相对远离直接的岩浆作用。矿体均赋存于地层中,具多时代多层位赋矿特征,成矿温度低于300℃,矿体受深大断裂控制明显,矿床类型以卡林型金矿为主,次有凝灰岩型金矿。但是,两类矿床的原生矿石性质一致,而且成矿时代是基本一致的,二者只是赋矿层位不同而已。据此研究表明,该区不同层位、不同类型金矿是受深大断裂和深源流体统一制约,并伴随深源流体改造地壳岩石而发生多期多源叠加成矿的产物。

Abstract:

Southwestern Guizhou area is considered highly prospective for gold deposits and an important low-temperature mineralization area on the southwestern margin of the Yangtze platform. It is referred to as a low-temperature mineralization area because it is relatively far from direct magmatic sources, and thus the magmatic exposures are rare in this area. The gold ore bodies are generally hosted in the stratial horizons of different ages, and controlled by deep faults. The mineralization temperatures are less than 300℃. The gold deposits consist dominantly of Carlin-type gold deposits, with subordinate tuff-type ones. These types of gold deposits are identical in the nature of primary ores and mineralization ages of ore deposits, and only quite variable in host horizons. The results of research in the study show that all the gold deposits in varying horizons in this area are obviously constrained by deep faults and deep-seated fluids. The gold deposits have multiphase and polyphyletic origins, and resulted from the reworking of crustal rocks by deep-seated fluids.