地质与勘探2024，Vol.60Issue(2)：244-264,21.DOI:10.12134/j.dzykt.2024.02.004
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
Distribution and Precipitation Mechanism of Cobalt in the Zhongguan Skarn Iron Deposit in Hebei Province and Its Significance
摘要
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(below detection limit)～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.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Key words
cobalt/occurrence state/law of distribution/migration and precipitation mechanism/skarn/Zhongguan iron deposit/Hebei Province分类
天文与地球科学引用本文复制引用
张岱岳,曹冲,王树志,曹庆,董博萧,李悦,董桂玉,王玲..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):244-264,21.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. （编号:42002098）
