川滇黔相邻区碳酸盐岩容矿铅锌矿成矿特征
Mineralization of the carbonate-hosted Pb-Zn deposits in the SichuanYunnan-Guizhou area, southwestern China
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摘要: 本文对川滇黔相邻区碳酸盐岩容矿铅锌矿成矿特征进行系统总结,并对区域成矿过程进行讨论。该区碳酸盐岩容矿铅锌矿发育3种矿床类型,主要分布在泸定-荥经-汉源、雷波-金阳-巧家-会东、赫章-威宁-水城和会泽-彝良4个矿集区,震旦系和古生代地层为主要容矿层。铅锌矿形成于3个成矿期和3类构造环境:以黑区-雪区铅锌矿床为代表的喷流沉积型(SEDEX型),形成于早寒武世海底地震同生断裂环境;以会泽矿床为代表的与侵入作用有关的碳酸盐岩容矿铅锌银矿床类型(IRCH Pb-Zn-Ag型),形成于晚三叠世前陆早期局部引张环境;以大梁子和天桥矿床为代表的密西西比河谷型(MVT型),形成于前陆晚期冲断挤压环境。与世界其它地方不同,川滇黔相邻区MVT铅锌成矿作用主要发生于早侏罗世。Abstract: The present paper gives a detailed description of the mineralization of the carbonate-hosted Pb-Zn deposits in the Sichuan Yunnan-Guizhou area, southwestern China. Three types of the Pb-Zn deposits may be distinguished in the Luding-Yingjing-Hanyuan, Leibo-Jinyang-Qiaojia-Huidong, Hezhang-Weining-Shuicheng and Huize-Yiliang ore fields. The Sinian and Palaeozoic strata constitute the main host rocks of the Pb-Zn deposits outlined above. These Pb-Zn deposits are assigned to three types of mineralization and three types of tectonic settings, including the SEDEX-type deposit represented by the Heiqu-Xuequ Pb-Zn deposit formed in the Early Cambrian submarine seismic contemporaneous fault environment; the intrusion-related carbonate-hosted (IRCH) deposit represented by the Huize deposit formed in the extensional environment in the early stages of foreland thrust during the Late Triassic, and the Mississippi Valley-type (MVT) deposit represented by the Daliangzi and Tianqiao deposits formed in the late stages of foreland thrust and compression. Different from those in the other parts of the world, the mineralization of the Mississippi Valley-type Pb-Zn deposits in the study areas occurred mostly during the Early Jurassic.