| 辽东早元古代富镁质碳酸盐岩建造菱镁矿和滑石矿床成矿条件 |
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| 引用本文：.2003.Metallogenic Conditions of Magnesite and Talc Deposits in Early Proterozoic Mg-rich Carbonate Formations, Eastern Liaoning Province[J].Mineral Deposits,22(2):166~176 |
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| 基金项目:国际地质对比计划IGCP443项目和国土资源大调查项目(K1.4-1-5) |
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| 中文摘要:辽东地区早元古代大石桥组赋存有富镁质的碳酸盐岩建造，其中产有大型或超大型菱镁矿、滑石矿床。 文章在前人工作的基础上，结合近年来的野外调查和研究工作，从大地构造背景、含矿建造、岩相古地理、成矿构造、成矿流体等几方面讨论了辽东菱镁矿和滑石矿床的成矿条件。研究结果表明，该地区菱镁矿矿床是元古代海相蒸发沉积条件下形成的，而滑石矿床则是由埋藏海水演化而来的富硅质高盐度的变质流体对镁质碳酸盐岩交代的产物。 |
| 中文关键词:地质学 菱镁矿 滑石 成矿条件 辽东 早元古代 |
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| Metallogenic Conditions of Magnesite and Talc Deposits in Early Proterozoic Mg-rich Carbonate Formations, Eastern Liaoning Province |
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| Abstract:A number of large and superlarge magnesite and talc deposits occur in Mg_rich carbonate strata of Early Proterozoic Dashiqiao Formation in eastern Liaoning Province. The existence of sedimentary gypsum and the δ18O,δ13C, δ34S isotopic geochemistry as well as Sr/Ba ratios of carbonate, talc, quartz and gypsums in combination with field investigation and laboratory sample analysis demonstrate that the formation of magnesite and talc deposits was closely related to marine evaporates, which underwent reformation as a result of regional metamorphism and hydrothermal metasomatism. Metasomatic fluids derived from paleoseawater played a controlling role in the formation of talc deposits. In this paper, the authors deal with the ore-forming conditions of magnesite and talc deposits, such as their tectonic setting, the ore-bearing formation, the lithological and palaeo_geographic features, the ore-forming structures, and the origin and evolution of the ore-forming fluids. It is held that the magnesite deposits were mainly formed by evaporation and sedimentation in a marine environment, whereas the talc deposits resulted from the metasomatism of the Mg_rich carbonates by the action of SiO2_rich saline hydrothermal fluids during regional metamorphism. |
| keywords:geology, magnesite, talc, ore-forming condition, Eastern Liaoning Province, Early Proterozoic |
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