个旧老卡岩体凹陷带岩矿特征与成矿机理分析

Mineralogical and lithological features and metallogenic mechanism of the depression zone of Laoka granite in the Gejiu tin-polymetallic orefield,Yunnan province

对云南个旧矿田的典型控矿地带——老卡岩体凹陷带内的矿化特征、岩相学及矿相学特征和流体包裹体进行分析,进一步研究花岗岩凹陷带的成矿机理。研究认为变玄武岩中普遍发育的金云母化是导致变玄武岩型矿床中锡矿化与金属硫化物伴生的原因之一,凹陷带内带所见的金云母化和绢云母化都与成矿有着密切的关系。花岗岩凹陷带的成矿作用经历了花岗岩侵位、花岗岩叠加改造玄武岩内的"矿胚"、花岗岩蚀变、矿化沉淀这四个过程。

This research deals with the metallogenic mechanism of the depression zone of Laoka granite in the Gej iu tin-polymetallic orefield,Yunnan province based on the analysis of the characteristic of mineralization, mineral and lithological features and fluid inclusions.It is shown that the alteration of widely developed phlogopite in altered basalt is one of the reasons for the association of tin with metal sulfides.Both the alter-ation of phlogopite and sericitization in the granite depression zone have a close relationship with mineraliza-tion.The mineralization of the granite depression zone underwent four processes：granite invasion,overlay and reform of the＂ore embryo＂in basalt by the granite,granite alteration and ore precipitation.