云南澜沧老厂多金属矿床隐伏斑岩流体包裹体研究

The Fluid Inclusions Study in Concealed Porphyry of Laochang Polymetallic Deposits,Lancang,Yunnan Province,China

云南澜沧老厂多金属矿床是三江成矿带南段最重要的多金属矿床之一,为研究其成因,对其开展了系统的地质及成矿流体特征研究。根据矿脉穿切关系,热液成矿过程可分为4个阶段。流体包裹体岩相学研究结果表明,矿床主要发育3类包裹体:Ⅰ型富液的两相包裹体、Ⅱ型富气的两相包裹体、Ⅲ型含子晶的三相包裹体。显微测温显示成矿流体从早期到晚期呈现从高温高盐度流体向低温低盐度流体演化的趋势,成矿流体在演化过程中的冷却作用是矿床沉淀成矿的主要因素。

The Laochang poly-metallic deposit is one of the most important deposits in southern Sanjiang metallogenic belt.This paper systematically studied on geology and nature of ore-forming fluids of the deposit. According to the geological relationship of ore-bearing veins,the ore-forming process can be divided into 4 stages. There are 3 types of fluid inclusions:type-Ⅰ of two-phase fluid-rich,type-Ⅱ of two-phase vapour-rich,type-Ⅲ of daughter mineral-bearing three-phase. The results suggested that the ore-forming fluids experienced the evolution from high temperature and high salinity to low temperature and low salinity. It is thus proposed that the cooling of fluids is main factor for precipitating metals in the evolution process of the ore-forming fluids.