| 白垩系膏岩层序对铅锌矿床形成的贡献——以云南兰坪金顶超大型铅锌矿床云龙组为例 |
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| 关键词:Yunlong Formation gypsum-bearing sequence Cretaceous ore formation Jinding zinc-lead deposit Lanping basin |
| 基金项目:国家重点研发计划“深地资源勘查开采”重点专项(编号: 2016YFC06003);国家自然科学基金项目(编号: U09933605; 41373049);中国地质调查局地质调查项目(编号: 1212011121065; 1212011020000150011) |
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| Contribution of the Cretaceous Gypsum Sequence to Zinc-lead Ore Formation: A Case Study of the Yunlong Formation at the Jinding Superlarge Zinc-lead Deposit in Lanping Basin, Yunnan Province |
| Based on field survey and geological observations and combined with exploration data and previous studies, the authors used the clay mineral K-Ar dating methods to conduct preliminary research on illites in the Yunlong Formation of the supergiant Jinding Zn-Pb deposit in the Lanping basin of Southwest China as well as the main orebodies, ores and host rocks in typical geological section along No. 12 exploration line. An analysis of the textures and structures of the orebodies shows that the gypsum salt sequences in the deposit may have undergone sulfate reduction. The age of (105.7±1.4) Ma of K-Ar dating of the illites in the Yunlong Formation, which is similar to the previous Re-Os isochron age of (114±13) Ma, indicates that the gypsum sequence of the Yunlong Formation should belong to the Cretaceous Albian period. The salts in the Jinding Zn-Pb ore district occur in the middle and upper parts of the Yunlong Formation with stratoid, lenticular, and brecciated shapes. After the late mineralization transformation, the orebodies also exhibited stratoid, irregular, and breccia forms, with the lead-zinc orebodies usually coexistent with gypsum. The space occupied by the lead-zinc orebodies may be either the location of the original gypsum salt sequence or the pores of the Jingxing Formation sandstones with high porosity. The huge amount of gypsum hosted in the Yunlong Formation provided abundant sulfur through sulfate reduction during the ore-forming process, which caused the Jinding lead-zinc deposit to reach a superlarge scale. Therefore, the consumption of gypsum formation is one of the key factors for the formation of the Jinding supergiant Zn-Pb deposit. It has universal significance in the search for Zn-Pb ore deposits related to the gypsum sequences in the Tethys domain. The comparative study of such gypsum sequences of the Yunlong Formation is of great significance for the judgment of the regional prospecting potential of the “Jinding-style” MVT Zn-Pb deposits. |
| ZENG Zhao-yang,XUE Chuan-dong,LIU Jing-kun.2020.Contribution of the Cretaceous Gypsum Sequence to Zinc-lead Ore Formation: A Case Study of the Yunlong Formation at the Jinding Superlarge Zinc-lead Deposit in Lanping Basin, Yunnan Province[J].Acta Geoscientica Sinica,41(5):723-738. |
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