| 河北中关矽卡岩铁矿床钴元素分布规律与沉淀机制研究及意义 |
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| 引用本文： | 张岱岳. 河北中关矽卡岩铁矿床钴元素分布规律与沉淀机制研究及意义[J]. 地质与勘探, 2024, 60(2): 244-264 |
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| 作者姓名： | 张岱岳 |
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| 作者单位： | 华北理工大学,河北唐山;中国科学院大学,北京 |
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| 基金项目： | 国家自然科学基金项目(编号：42002098)、河北省钢铁实验室研究项目（编号：23564201D）、河北省自然科学基金项目（编号：D2023209016、D2020209017、D2020209003、E2022209119、236Z3804G）与河北省研究生创新项目(编号：CXZZBS2021103)联合资助 |
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| 摘 要： | 河北中关铁矿是“邯邢式”矽卡岩铁矿的代表矿床,本文将中关铁矿床成矿过程划分为5个阶段：干矽卡岩阶段、湿矽卡岩阶段、氧化物阶段、铁铜硫化物阶段和铅锌硫化物阶段。对湿矽卡岩阶段、氧化物阶段和铁铜硫化物阶段的金属矿物（包括黄铁矿、磁铁矿、赤铁矿等）开展电子探针测试,并且对这三个成矿阶段的代表性磁铁矿进行LA-ICP-MS微量元素测试,旨在查明中关铁矿床中Co的赋存状态以及在矿床不同成矿阶段的分布规律,探讨Co元素迁移演化-沉淀机制。研究结果表明,Co主要以类质同象的形式存在于黄铁矿中。不同成矿阶段的Co元素分布不均匀,氧化物阶段黄铁矿和磁铁矿中的Co含量最高,分别为0.12%~1.39%、41×10-6~76×10-6;铁铜硫化物阶段黄铁矿大量出现,且Co含量相对较高,为BDL~0.45%,同时期条带状磁铁矿为32×10-6~71×10-6,故此阶段为Co元素最主要的富集阶段。湿矽卡岩阶段为较高温、弱氧化条件,氧化物阶段温度逐渐降低,氧逸度增加,Co可能主要以CoCl42?形式络合迁移;铁铜硫化物阶段温度进一步降低,但还原性增加,Co可能主要以CoCl42?和Co(HS)+形式络合迁移。温度降低以及氧化还原条件的变化可能是控制Co沉淀的重要因素。
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| 关 键 词： | 钴 赋存状态 分布规律 迁移和沉淀机制 矽卡岩 中关铁矿 河北 |
| 收稿时间： | 2023-04-14 |
| 修稿时间： | 2023-09-11 |
Distribution and precipitation mechanism of cobalt in the Zhongguan skarn iron deposit in Hebei Province and its significance |
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| Zhang Daiyu. Distribution and precipitation mechanism of cobalt in the Zhongguan skarn iron deposit in Hebei Province and its significance[J]. Geology and Prospecting, 2024, 60(2): 244-264 |
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| Authors: | Zhang Daiyu |
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| Affiliation: | North China University of Science and Technology, Tangshan, Hebei; University of Chinese Academy of Sciences, Beijing |
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| Abstract: | The Zhongguan iron deposit is a representative Hanxing-type skarn iron deposit, and the ore-forming process of this deposit is divided into five stages: dry skarn stage, wet skarn stage, oxide stage, iron-copper sulfide stage and lead-zinc sulfide stage. In this paper, electron probe tests were carried out on the metallic minerals (including pyrite, magnetite, hematite, etc.) in the wet skarn stage, oxide stage and iron-copper sulfide stage, and LA-ICP-MS tests were carried out to analyze the trace elements of representative magnetite in each ore-forming stage to determine the occurrence state of Co and ascertain its distribution law in the Zhongguan iron deposit. Furthermore, the migration evolution and precipitation mechanism of Co element were discussed. The results show that Co mainly occurs in pyrite in the form of homomorphism. The content of Co from different ore-forming stages varies greatly. The content of Co in pyrite and magnetite at oxide stage is the highest (0.12%~1.39% and 41×10-6~76 ×10-6, respectively). A large amount of pyrite appears in the Fe-Cu sulfide stage, the Co content of which is relatively high (BDL~0.45%). The Co content of contemporaneous magnetite is 32×10-6~71×10-6. Therefore, this stage is the most important enrichment stage of Co element. It is considered that the wet skarn stage was formed under high temperature and weak oxidation condition. When comes to oxide stage, the temperature of ore-forming fluid decreased, oxygen fugacity further increased, and Co mainly migrated in the form of CoCl42? complexation. In the iron-copper sulfide stage, the temperature further decreased and the ore-forming fluid was significantly reduced. Co migrated mainly in the form of CoCl42? and Co(HS)+. The decrease of temperature and the change of redox state are the main factors resulting in the precipitation of Co. |
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| Keywords: | cobalt occurrence state law of distribution migration and precipitation mechanism skarn Zhongguan iron deposit Hebei Province |
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