西藏雄村大型铜金矿床的特征、成因和动力学背景  

The Xiongcun Copper-gold Deposit in Tibet:Characteristics, Genesis, and Geodynamic Application

作　　者：徐文艺[1] 曲晓明[2] 侯增谦[3] 杨竹森[2] 潘凤雏 崔艳合[1] 陈伟十[1] 杨丹[1] 连玉[1] 

机构地区：[1]中国地质科学院矿产资源研究所成矿作用与资源评价重点实验室,北京100037 [2]中国地质科学院矿产资源研究所,北京100037 [3]中国地质科学院地质研究所,北京100037 [4]西藏地质调查研究院,拉萨850000

出　　处：《地质学报》2006年第9期1392-1406,T0002,共16页Acta Geologica Sinica

基　　金：科技部"973"计划项目(编号2002CB412605);国家自然科学基金项目(编号40303008)资助成果

摘　　要：详细的蚀变矿化特征剖析揭示,雄村矿床的矿化样式可明显地区分为两种类型,即早期的细脉浸染状Cu-Au矿化和晚期的脉型金(银)-多金属矿化。早期细脉浸染状矿化的蚀变组合为:(钠长石化)-钾硅酸盐蚀变(局部)-红柱石化-广泛的绢英岩化-绿泥石化(青磐岩化?);晚期脉型金(银)-多金属矿化蚀变组合为:强烈硅化-绿泥石化-高岭石化。蚀变矿化组合、流体包裹体测试结果及稳定同位素(H、O、S)组成揭示,早期细脉浸染状Cu-Au矿化可能属于未发育成熟的斑岩型矿化,晚期脉型金(银)-多金属矿化为介于高硫型与低硫型之间的过渡型浅成热液矿化。雄村矿床可能为一套生矿床,是未发育成熟的斑岩型矿化与浅成热液型矿化套生的产物;成矿流体组成上的一致性,表明套生的两期矿化可能属于同一热液体系的两个连续的矿化阶段,只是在两个矿化阶段成矿环境发生了较大改变。热液绢云母40Ar/39Ar测年和似伟晶岩脉中的钾长石K-Ar测年,表明雄村成矿系统形成于47.62±0.7Ma^38.11±0.9Ma间,与喜马拉雅—青藏高原造山带52~40Ma间歇性松弛或N-S向伸展有关;但雄村矿床的最终套生定位,与造山带40~38Ma间的强烈挤压隆升有关。According to the alteration and mineraliazation assemblage, mineralizations in Xiongcun deposit can be obviously distinguished into two styles, i.e. early veinlet-disseminated Cu（Au） mineralization with associated albitization, local K-silicate alteration, andalusite alteration, extensive phyllic alteration and peripheral widespread propylitization, and late vein-style Au （Ag） -polymetallic mineralization with associated strong silicification, chloritization and kaolinization. The latter overprints the former. The H, O and S isotopic compositions and the high salinities of fluid inclusions indicate the magmatic contributions and the increasing contents of meteoric water in the mineralizing system from early to late. The early veinlet-disseminated Cu （Au） mineralization is similar to porphyry-type mineralizaiton and maybe belongs to an immature porphyry system. The late vein-style Au （Ag）-polymetallic mineralization, characterized by high salinity and high base metal contents, belongs to the transitional system between end-member high- and low-sulfidation-type epithermal systems. Xiongcun deposit is a telescoping system of above two. Sericite ^40Ar/^39Ar dating reveals the ore-forming age of Xiongcun deposit is 38. 11 ± 0. 9Ma. K-feldspar K-Ar age of the K-feldspar-muscovite- tourmaline-pyrite pegmatoid dyke in Xiongcun is 47. 62± 0.7 Ma. These ages indicate that the mineralizing system in Xiongcun results from the intervallic relaxation （ca. 52-40 Ma） of the Himalayan-Tibetan orogen and the final telescoping from the proceeding rapid uplifting （40-38 Ma） of the orogen.

关 键 词：喜马拉雅-青藏高原造山带 雄村 套生矿床 ^40Ar/^39Ar测年 

分 类 号：P618.2[天文地球—矿床学]