班公湖—怒江成矿带西段主要岩浆热液型矿床成矿特征初探

摘要

With magmatic-hydrothermal mineralization as the topic, this paper summarized the spatial distribution and mineralization types of the main ore deposits in the western Bangong Co–Nujiang metallogenic belt and investigated their metallogenic epochs. Six mineralization events were recognized, i.e., the early stage of Late Jurassic, the late stage of Late Jurassic, the late stage of Early Cretaceous, the middle stage of Late Cretaceous, the late stage of Late Cretaceous, and the Miocene period. On such a basis, this paper illustrated the mineralization features of the main ore deposits and compared the differences of basic geological characteristics, major elements, rare earth elements and trace elements compositions between the ore-forming intrusions. Based on studying Hf isotope of zircons from ore-forming intrusive rocks and Re content of molybdenite of the main ore deposits, the authors clarified the relationship between different diagenetic-metallogenetic material sources and mineralization elements associations, i.e., the more mixed mantle derived materials in the ore-forming process, the more possible the formation of the Cu-Au mineralization association. Based on the current prospecting and exploration extent, the regularity of the main magmatic-hydrothermal ore deposits was summarized, and the deposit types expected to make breakthrough and their corresponding target areas were also analyzed.%文章对班公湖—怒江成矿带西段与岩浆热液有关的主要矿床空间分布、矿化类型进行了总结;对主要成矿事件形成时代进行了统计,识别出6期成矿事件,分别为晚侏罗世早期、晚侏罗世晚期、早白垩世晚期、晚白垩世中期、晚白垩世晚期和中新世.基于前人研究成果,对主要矿床地质特征、成矿岩浆岩基本地质特征、岩石地球化学特征进行了阐述和对比研究,明确了成矿岩体特征之差异.通过对班—怒成矿带西段主要矿床成矿岩体锆石Hf同位素和辉钼矿Re含量的梳理,阐明了成岩-成矿物质源区差异与矿化元素组合之间的耦合关系,即幔源物质参与成矿强度大,形成铜金矿.最后,文章对区域成矿特征进行了总结梳理,并提出了班公湖—怒江成矿带西段可望取得找矿新进展的矿床类型和找矿方向.