富碱侵入岩与金成矿关系:云南省姚安金矿床成矿流体形成演化的微量元素和同位素证据  

Trace element and isotope evidence for the evolution of ore-forming fluid of Yao'an gold deposit, Yunnan Province, China

作　　者：毕献武[1] 胡瑞忠[1] D.H.Cornell 

机构地区：[1]中国科学院地球化学研究所,贵州贵阳550002 [2]Department of Geology Gotenburg University

出　　处：《地球化学》2001年第3期264-272,共9页Geochimica

基　　金：国家杰出青年基金(49925309);国家重点基础研究发展规划项目(G1999043209)

摘　　要：以产在姚安富碱侵入岩体内外接触带上的姚安金矿床为对象,对成矿流体形成演化过程中的微量元素和S、C同位素地球化学进行了综合研究。研究结果表明,富碱侵入岩成岩过程中分异出的岩浆流体提供了姚安金矿床早期成矿作用所必需的成矿流体;从早期成矿阶段至晚期成矿阶段,成矿流体经历了从以岩浆流体为主的流体体系至以大气降水为主的流体体系的转变。因此,钙碱性侵入岩成岩过程中可分异出成矿流体的过程,也存在于富碱侵入岩的成岩过程中。Trace element, sulfur and carbon isotope geochemistry was applied to the formation and evolution of ore forming fluids in the Yaoan gold deposit of Yunnan Province, China. The results show that magmatic fluids generated during the petrogenesis of the alkali rich intrusives caused both potassic alteration and early stage Ⅰ sulfide mineralization of the Yaoan gold deposit. The later stage Ⅱ fluids had very different REE character, with much lower levels and flatter chondrite normalized patterns, combining with quartz, calcite and chlorite as the main gangue minerals in this stage, reflecting a lower temperature environment. From stageⅠ to stage Ⅱ (sulfide plus oxide), the fluids evolved from the system dominated by magmatic fluids to that by meteoric fluids. This ore forming fluid evolution is analogous to that found in the petrogenesis of calc alkaline intrusive rocks. This type of gold mineralization associated with alkali rich intrusives is probably more widespread than presently realized.

关 键 词：富碱侵入岩 金矿床 成矿流体 微量元素 同位素 成矿作用 矿床成因论 云南 

分 类 号：P618.51[天文地球—矿床学] P59[天文地球—地质学]