云南个旧矿集区区域构造-岩浆演化与锡铜多金属成矿系统

Tectono-Magmatic Evolution Related to Metallogenic System in Gejiu Ore-Concentration Area,Southeast Yunnan of China

个旧矿集区是滇东南最重要的锡铜多金属矿产地之一,形成了云英岩-石英脉型矿化、与矽卡岩化有关的锡石-硫化物型矿化、蚀变基性火山-次火山岩型矿化和与断裂有关的各种脉型矿化构成的锡铜多金属成矿系统.根据区域构造-岩浆演化与锡铜多金属矿化系统的配置关系研究,认为燕山晚期复式花岗岩体侵位进入以中三叠统为主的碳酸盐岩地层组成的褶皱带中,锡铜等金属元素的成矿富集产生于花岗岩体与围岩接触带及其附近发生的接触交代和更远处发生的交代-充填过程,成矿元素主要源自燕山期中下部地壳物质熔融形成的花岗岩浆和印支期裂谷环境中来自地幔的玄武岩-辉绿岩-辉长岩类,多期脉动式的岩浆活动驱动了一个长效的热液系统,这些要素共同构筑了这一巨量的金属矿集区.由此建立了个旧矿集区的区域成矿模型,并对进一步寻找新的矿化类型提出了理论线索.

Gejiu ore-concentration area is one of the most important occurrences of Sn-Cu polymetallie mineralization in Southeast YunnarL Sn-Cu polymetallic system of mineralization in the area includes Sn-W greisen-quartz vein type, Cu-massive-sulfide cassiterite type, Cu-Sn altered-basic-rock type, and Sn-Pb-Zn vein types of deposits. The study of the relationship between the tectono-magmatic evolution and the Gejiu system of mineralization shows that Sn-Cu polymetal enrichment occurred in and near the contact zone between granite and wall rock through contact metamorphism, metasomatic and filling processes, when the composite granites invaded into folded limestones of Middle Triassic （Gejiu Formation）. These metals may come from two reservoirs, i.e. granitic magma originated from the middle-lower crust in the Yenshan period and basalt-diabase-gabbro from the mantle in the Indo-Chinese period. Pulsatory magmatic activities are believed to be the main driving force for the formation of the hydrothermal system for the ore-forming progress. A regional model of mineralization is proposed in this study for assisting mineral exploration and prediction for new types of mineral deposits in this area.