投稿时间：2024-11-23
修订日期：2025-01-20
网络发布日期：2025-03-10
中文摘要:沉积型锰矿和沉积（变质）型铁矿在地球历史上具有明显的时控特征，前者集中形成于古元古代、新元古代和显生宙，后者主要形成于古元古代大氧化事件之前和新元古代；在空间上可表现为数百公里至上千公里的铁、锰分离。铁、锰分离的控制因素主要包括：① 锰与铁元素的地球化学行为不同，如在pH ＞ 7.78时锰单独沉积，pH值在6.5~8.0之间铁、锰可同时沉淀，pH ＜ 7.78铁则单独沉淀；② 原始含铁、锰物质溶解度的差异引起铁、锰浸出率的不同；③ 海洋氧化还原环境的变化；④ 早期黄铁矿在缺氧还原条件下的优先沉淀；⑤ 来自陆源的可溶性Fe2+和Mn2+在海水介质中，由于胶体或有机颗粒吸附和自身氧化作用能力的不同。综合研究表明铁锰分离是锰沉积成矿的必经过程，不同沉积锰矿床的铁、锰分离程度（Mn/Fe值）差异较大，海洋环境中的铁、锰分离和富锰成矿过程主要受控于次氧化条件下铁的优先氧化或缺氧硫化条件下黄铁矿的大量沉淀。
Abstract:Sedimentary manganese deposits and sedimentary (metamorphic) iron deposits show significant time-controlled characteristics in earth history, the former mainly concentrated in the Paleoproterozoic, Neoproterozoic and Phanerozoic, while the latter mainly formed before the Great Oxidation Event in the Paleoproterozoic and Neoproterozoic. In space, the separation of iron and manganese can be hundreds to thousands of kilometers. The control factors of iron and manganese separation mainly include: ① The geochemical behavior of manganese and iron is different, such as manganese deposition alone when pH ＞ 7.78, iron and manganese can be precipitated simultaneously between pH 6.5 and 8, and iron can be precipitated separately when pH ＜ 7.78; ② The difference in solubility of the original Fe-Mn substance leads to the difference in the leaching rate of Fe-Mn; ③ Changes of marine redox environment; ④ Preferentially precipitation of early pyrite under hypoxic reduction conditions; ⑤ Soluble Fe2+ and Mn2+ from terrestrial sources are different in the seawater medium due to the adsorption and self-oxidation of colloidal or organic particles. Comprehensive studies show that Fe-Mn separation is a necessary process for manganese deposition and mineralization, and the degree of Fe-Mn separation (Mn/Fevalue) varies greatly among different sedimentary manganese deposits. Fe-Mn separation and manganese-rich mineralization processes in marine environment are mainly controlled by preferential oxidation of iron under secondary oxidation conditions or mass precipitation of pyrite under anoxic vulcanization conditions.
keywords:Mn/Fe ratio separation of iron and manganese manganese-rich deposit sedimentary metallogenic mechanism sedimentary manganese deposit
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基金项目:本文得到国家重点研发计划项目（编号：2022YFC2903502）和国家自然科学基金项目（编号：U1703242，42302081）联合资助
引用文本：
张连昌,李文君,董志国,李文,徐一帆,高炳宇,王长乐,朱明田.2025.沉积锰矿成矿过程中铁锰分离与富锰矿形成机制[J].矿床地质,44(1):85~100ZHANG LianChang,LI WenJun,DONG ZhiGuo,LI Wen,XU YiFan,GAO BingYu,WANG ChangLe,ZHU MingTian.2025.Iron-manganese separation and formation mechanism of manganese-rich ore during ore-forming processes of sedimentary manganese deposit[J].Mineral Deposits44(1):85~100
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