云南沧源拱丁金多金属矿床的成矿特征及成因

Characteristics and Genesis of the Gongding Gold-polymetallic Deposit,Cangyuan County,Yunnan Province

云南沧源拱丁金多金属矿床产于耿马花岗岩西接触带内带的构造破碎带中,矿体呈脉状,形态单一。矿石和脉石矿物的S、Pb同位素、流体包裹体的均一温度和成矿流体成分的分析结果表明,成矿流体来源于天水和岩浆流体的混合,成矿组分主要是从元古界地层中萃取的,但也包含有岩浆热液携带的深部成矿物质。成矿温度为217～353℃,属于中高温热液矿床。根据矿床的空间分布、围岩蚀变类型以及成矿时代分析,提出燕山晚期中酸性岩脉发育地段,特别是闪长玢岩岩脉群分布地段以及耿马花岗岩体与元古界西盟群王雅组接触带内带的构造破碎带,是重要的找矿标志和找矿方向。

The Gongding gold-polymetallic deposit of Cangyuan, western Yunnan occurs in a fracture zone in inner contact of western margin of the Gengma granite pluton. The ore bodies are simply vein-shaped. Analyses of S and Pb isotopes, and homogenization temperature and composition of fluid inclusions have been conducted. The results show that the ore-forming fluids likely the metals might be extracted from the Proterozoic came from meteoritic water mixed with magmatic fluids, and strata, with some kinds of deep source metallic components carried by magmatic fluids. The homogenization temperature is 217 -353℃ , belonging to intermediate-high temperature hydrothermal deposit. According to the spatial distribution of the ore deposit, wall-rock alteration and the timing of the ore formation, two types of settings could be of great potential for further prospecting. One is the setting where late-Yanshanian intermediate-acidic dikes, especially dioritic dikes, are concentrated; the other is fracture zones within inner contact of the Gengma granite pluton with the Proterozoic Ximeng Formation.