| 南秦岭地区下寒武统黑色页岩赋存的千家坪大型钒矿地球化学特征及成矿环境 |
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| 引用本文： | 徐林刚,付雪瑞,叶会寿,郑伟,陈勃,方正龙.南秦岭地区下寒武统黑色页岩赋存的千家坪大型钒矿地球化学特征及成矿环境[J].地学前缘,2022,29(1):160-175. |
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| 作者姓名： | 徐林刚 付雪瑞 叶会寿 郑伟 陈勃 方正龙 |
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| 作者单位： | 1.中国地质大学(北京) 地球科学与资源学院, 北京 1000832.自然资源部战略性金属矿产找矿理论与技术重点实验室, 北京 1000833.中国地质科学院 矿产资源研究所, 北京 1000374.陕西华源矿业有限责任公司, 陕西 商洛 726000 |
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| 基金项目： | 中国地质大学(北京)拔尖青年教师创新能力培养项目;国家自然科学基金 |
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| 摘 要： | 南秦岭地区下寒武统黑色页岩是我国主要的富钒层位,其中千家坪大型钒矿是典型代表。矿体主要赋存在水沟口组第一岩性段的碳硅质岩石中。为了探讨钒矿的成矿物质来源和南秦岭早寒武世古海洋氧化-还原环境,本文对水沟口组第一岩性段富钒碳硅质岩和上覆的第二岩性段泥质灰岩开展了岩石地球化学研究。第一岩性段碳硅质岩比第二岩性段泥质灰岩具有更高的Y/Ho比值,说明碳硅质岩主要为海水自生沉积形成的,而泥质灰岩的物质组成主要来自陆源碎屑。Eu/Eu*与V含量不具备正相关关系,且Y/P2O5-Zr/Cr和Fe/Ti-Al/(Al+Fe+Mn)图解均显示钒矿主要是海水沉积形成的,热液作用对成矿元素的富集贡献很小。水沟口组样品Ce/Ce*均为负异常,变化范围为0.26~0.96,第一岩性段钒矿石比第二岩性段泥质灰岩具有高Mo/Sc、V/Sc、V/Cr比值,低Th/U比值的特征,反映了早寒武世早期南秦岭为氧化-还原分层的古海洋结构,而晚期古海洋则全部被氧化。
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| 关 键 词： | 千家坪钒矿 微量元素 稀土元素 矿床成因 氧化-还原环境 南秦岭 |
| 收稿时间： | 2021-04-25 |
Geochemical composition and paleoceanic environment of the Lower Cambrian black shale-hosted Qianjiaping vanadium deposit in the southern Qinling Region |
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| XU Lingang,FU Xuerui,YE Huishou,ZHENG Wei,CHEN Bo,FANG Zhenglong.Geochemical composition and paleoceanic environment of the Lower Cambrian black shale-hosted Qianjiaping vanadium deposit in the southern Qinling Region[J].Earth Science Frontiers,2022,29(1):160-175. |
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| Authors: | XU Lingang FU Xuerui YE Huishou ZHENG Wei CHEN Bo FANG Zhenglong |
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| Institution: | 1. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing 100083, China2. Key Laboratory for Exploration Theory & Technology of Critical Mineral Resources, Ministry of Natural Resources, Beijing 100083, China3. Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China4. Shaanxi Huayuan Mining Co., Ltd., Shangluo 726000, China |
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| Abstract: | The Qianjiaping vanadium (V) deposit is a typical Lower Cambrian black shale-hosted V deposit in the Southern Qinling Region. Vanadium mineralization in the Qianjiaping deposit mainly occurs in multilayered cherts with carbonaceous shale in the 1st member of the Shuigoukou Formation. To better understand the origin of vanadium and redox environment in Early Cambrian seawater in South Qinling, we report in this study the bulk geochemical compositions of the V-rich carbonaceous shale from the 1st member and the overlying muddy limestone from the 2nd member of the Shuigoukou Formation. The Y/Ho ratio is higher in the multilayered chert-mudstone samples than in the muddy limestone samples, indicating a dominant authigenic origin for V in the 1st member, whereas in the 2nd member V may be mostly derived from detrital components. Discrimination plots, Eu/Eu*-V, Y/P2O5-Zr/Cr and Fe/Ti-Al/(Al+Fe+Mn), suggest V mineralization is mainly by precipitation from ambient seawater, while hydrothermal fluids plays a minor role. All samples showed negative Ce anomaly, ranging from 0.26-0.96. Together considering the comparatively high Mo/Sc, V/Sc, V/Cr and low Th/U ratios in the 1st member, we infer a redox stratified ocean during the early Early Cambrian in the Southern Qinling Region, which became entirely oxygenated during the late Early Cambrian. |
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| Keywords: | Qianjiaping vanadium deposit trace element REE ore genesis redox environment Southern Qinling Region |
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