新疆雅满苏铁矿区碳酸盐岩地质地球化学特征及其对矿床成因的制约

发布时间：2018-05-26 22:36

本文选题：地球化学 + 碳酸盐岩　；参考：《矿床地质》2017年01期

【摘要】：新疆雅满苏铁矿床赋存于下石炭统雅满苏组中,矿区发育火山岩、碳酸盐岩及矽卡岩,因此,研究碳酸盐岩与矽卡岩及成矿的关系对厘定矿床成因类型和指导找矿勘查具有重要的理论和实际意义。文章在野外地质剖面测制和调查研究的基础上,对矿区及外围碳酸盐岩进行了岩相学、主量元素、稀土元素及微量元素分析,探讨了矿区碳酸盐岩的地质、地球化学特征。研究结果表明,雅满苏铁矿区的碳酸盐岩含有浅海相生物化石、鲕粒结构及内碎屑构造,与火山岩互层产出,指示沉积作用及火山喷发活动发生于浅海环境;矿区碳酸盐岩岩石类型包括微晶灰岩、细晶灰岩、大理岩、含凝灰质大理岩、糜棱岩化碳酸盐岩和方解石构造片岩,它们的主量元素含量差别不大,说明在变质变形和成矿作用过程中没有主量元素组分的明显带入带出;稀土、微量元素含量除方解石构造片岩稍有降低外,其余岩性均变化不大,也表明变质变形和成矿作用过程中没有外来物质的明显加入,包括成矿物质;与矿体毗邻的碳酸盐岩为方解石构造片岩,没有发生矽卡岩化,表明该碳酸盐岩在构造及成矿作用过程中只发生了构造片理化和热液重结晶,没有发生接触交代。因此,雅满苏铁矿床不是狭义的矽卡岩(接触交代)型铁矿床,而是海相火山岩型铁矿床。研究区的矽卡岩并非是接触交代的产物,而应是火山热液交代含碳酸盐的火山岩而成。是否有下部地层中的碳酸盐岩提供成岩成矿物质还需要进一步研究。
[Abstract]:The Yamen cycad deposit in Xinjiang is located in the Yamansu formation of Lower Carboniferous. Volcanic rock, carbonate rock and skarn are developed in the ore area. The study of the relationship between carbonate rock and skarn and mineralization is of great theoretical and practical significance in determining the genetic types of ore deposits and guiding prospecting and exploration. On the basis of field geological profile survey and investigation, the lithofacies, principal elements, rare earth elements and trace elements of carbonate rocks in and around mining areas are analyzed, and the geological and geochemical characteristics of carbonate rocks in mining areas are discussed. The results show that the carbonate rocks in the Yamen Cycas deposit contain shallow marine biota, oolitic structure and internal clastic structure, interbedded with volcanic rocks, indicating that sedimentary processes and volcanic eruptions occurred in the shallow sea environment. The types of carbonate rocks in the mining area include microcrystalline limestone, fine-grained limestone, marble, tuffaceous marble, mylonitic carbonate rock and calcite schist. It shows that during metamorphic deformation and mineralization, there is no obvious bring out of the principal element components, and the contents of rare earth elements and trace elements except calcite structural schist decrease slightly, the other lithology changes little. It also shows that there is no obvious addition of foreign material, including the ore-forming material, during metamorphic deformation and mineralization, and that the carbonate rock adjacent to the orebody is calcite schist, and no skarn occurs. The results show that only the tectonics, hydrothermal recrystallization and contact metasomatism occurred in the carbonate rocks during tectonic and metallogenic processes. Therefore, the Yamen cycad deposit is not a narrow skarn (contact metasomatic) iron deposit, but a marine volcanic ore deposit. Skarn in the study area is not the product of contact metasomatism, but is formed by volcanic hydrothermal metasomatism of carbonate bearing volcanic rocks. Whether carbonate rocks in the lower strata provide diagenetic minerals needs further study.
【作者单位】：中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室;新疆地矿局第六地质大队;
【基金】：国家自然科学基金项目(编号:41272102) 中国地质调查项目(编号:1212010733806、12120113092700)联合资助
【分类号】：P618.31

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