老挝色潘铜金矿床研究新进展

New Research Progress on Sepon Copper and Gold Deposits,Laos

色潘铜金矿集区是老挝镜内最大的铜金生产基地。铜金矿床的成矿作用与斑岩体密切相关,发育4种矿化类型,分别为斑岩体内部的斑岩型铜钼金矿化、斑岩体边部的类矽卡岩型铜金矿化、邻近斑岩体的碳酸盐岩交代型铅锌银矿化、远离斑岩体的沉积岩容矿型(类卡林型)金矿化。前三者成矿模式类同斑岩体系的"正岩浆模式",成矿作用与花岗闪长斑岩岩浆流体有关。沉积岩容矿型金矿化类同卡林型金矿化,但成矿热源及金属元素的来源可能与花岗闪长斑岩岩浆流体有关,大气降水混合循环作用是金沉淀的关键因素。因此,在矿集区范围内存在着成矿元素东西分带、内外分带现象,总体表现为斑岩体内部的高温矿化组合到远离中心的中低温矿化组合演化规律,即:Cu+Mo→Cu(Mo+Au+Ag)→Cu+Au(Ag)→Pb+Zn(Au+Ag)→Au+Ag。

The Sepon district is the biggest production base of copper and gold within Laos. The mineralization was closely associated with the porphyry systems in Sepon copper and gold deposits. Four main hypogene mineralization styles are recognized in sepon mine district as central porphyry （Cuq-Mo）, proximal skarn （Cu）, carbonate replacement （Pb＋Zn＋Ag）, and distal sedimentary-rock hosted gold （Carlin-like）. Metallogenic model of the former three is similar to ＂Normal magmatic mode＂ associtated with the porphyry systems. The mineralization related to magmatic fluids of granodiorite porphyries and dikes. The micro disseminated sediment-hosted gold has many similarities to the Carlin Tredn, Nevada, but the mineraliza- tion heat source and soure for metal elements might be related to the magmatic fluids of granitoid porphyrys. The atmospheric precipitation together with circulation is the key factor for gold precipitation. There- fore, it exists metallogenic element zoning from west to east, from inside to outside of the sepon mine districts. The overall performance is a gradual evolution from high temperature element mineralization in the central porphyry to mid-low temperature element mineralization, that is： Cu＋Mo→Cu（Mo＋Au＋Ag）→Cu＋Au（Ag）→Pb＋Zn（Au＋Ag）→Au＋Ag.