| 鄂西北地区银金多金属矿床地质特征与成矿规律 |
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| 引用本文： | 岳素伟,邓小华.鄂西北地区银金多金属矿床地质特征与成矿规律[J].地学前缘,2019,26(5):106-128. |
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| 作者姓名： | 岳素伟 邓小华 |
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| 作者单位： | 华南理工大学广州学院,广东广州,510800;北京矿产地质研究院,北京,100012 |
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| 基金项目： | 国家自然科学基金项目(41403032，41502070，41202050，41672079) |
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| 摘 要： | 鄂西北地区指湖北省武当山及其西北部等地，位于青峰断裂北侧，是秦岭成矿带的重要组成部分，以产银、金等多金属而闻名，蕴含了银洞沟、许家坡、佘家院、六斗等大中型银金(铅锌)或金(锑)矿床。根据区内矿床分布特征及控制因素，以十堰—鲍峡断裂为界将其划分为北带与南带。北带多以金、金锑矿床为主，沿郧阳—郧西断裂两侧分布，矿床多产在上覆陡山沱组地层和古生界地层中；南带主要有银洞沟银金矿床、许家坡金银矿床，矿床集中产于新元古界武当山群。区内矿床均受NW向韧性韧脆性剪切带及其次级断裂控制。碳氢氧同位素组成显示区内银金、金矿床成矿流体以变质热液为主，后期混入了大气降水，而金锑矿床可能为大气降水主导。硫同位素组成显示成矿流体的区域活动性和地层硫源特征。根据成矿元素的富集特征，下伏武当山群Cu、Pb、Zn、Au、Ag元素富集，在上覆陡山沱组、灯影组及古生界地层中依次出现Ag-Au、Au-Ag、Au、Au-Sb矿床，而在研究区西部的陕西境内泥盆纪地层有大量的Au-Sb、Hg-Sb矿。区内成矿元素的垂向分布特征符合地壳连续模式，矿床形成与地层本身具有较高丰度有密切联系，并在构造控制下就位。结合矿床地质、成矿流体及成矿时代，认为鄂西北地区银金、金、金锑矿床是形成于三叠纪古特提斯洋缝合过程中洋陆增生体制下的造山型矿床。
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| 关 键 词： | 银金多金属矿床 造山型矿床 成矿规律 鄂西北 |
| 收稿时间： | 2019-05-23 |
Geological and ore-forming characteristics of Ag-Au and polymetallic deposits in northwestern Hubei,China |
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| YUE Suwei,DENG Xiaohua.Geological and ore-forming characteristics of Ag-Au and polymetallic deposits in northwestern Hubei,China[J].Earth Science Frontiers,2019,26(5):106-128. |
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| Authors: | YUE Suwei DENG Xiaohua |
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| Abstract: | Northwestern Hubei Province, on the north side of the Qingfeng fault, is an important part of the Qinling metallogenic belt. It includes Wudangshan and its northwestern neighboring regions. Home to the Yindonggou, Xujiapo, Shejiayuan and Liudou large to medium-sized Ag-Au deposits, the area is famous for producing Ag, Au, Pb and Zn polymetallic minerals. It can be divided into the north and south belts according to the distribution characteristics and controlling factors of ore deposit. The north belt on the north side of the Qinggeng-Baoxi fault contains the Santianmen Au-Sb and Liudou Au deposits and many gold spots, distributed along both sides of the Yunxian-Yunxi fault. It mainly produces Au and Sb hosted in wall rocks of the overlying Doushantuo Formation and Palaeozoic strata. The south belt contains the Yindonggou large Ag-Au and Xujiapo medium Au-Ag deposits concentrated in the underlying Wudangshan Group. All deposits are controlled by toughness and NW-trending ductile brittle shear zone, with orebodies occurring in branch of brittle-fracture and fracture. Carbon, H and O isotopic compositions indicate the ore-forming fluids of Ag-Au and Au deposits are primarily metamorphic hydrothermal fluids that later mixed with meteoric water; while Au-Sb deposits accumulate towards the meteoric water line, indicating meteoric water may be dominant in the ore-forming fluids of Au-Sb deposit. Sulfur isotopic profile shows regional activity of ore-forming fluid and characteristics of strata-bound sulfur source. According to the enrichment characteristics of ore-forming elements, Cu, Pb, Zn, Au and Ag are enriched in the underlying Wudangshan Group, while Ag-Au/Au-Ag/Au and Au-Sb ore deposits occur in the overlying Doushantuo and Dengying Formations and Palaeozoic strata, respectively. In the western part of the study area, a large number of Au-Sb and Hg-Sb deposits are distributed in the Devonian strata of Shaanxi, suggesting a crustal continuum model for orogenic-type deposit. Clearly, under structural control, ore formation is closely related to the relatively high elemental abundance in the strata. Considering ore geology, ore-forming fluids and ore-forming age, we believe the northwestern Hubei Province Ag-Au and polymetallic deposits are orogenic type deposits, formed in accretionary orogens produced by the northward oceanic plate subduction along the Mian-Lüe Suture during the Triassic. |
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| Keywords: | Ag-Au and polymetallic deposits orogenic-type deposit ore-forming northwestern Hubei Province |
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