投稿时间：2015-05-15
修订日期：2016-08-24
网络发布日期：2017-03-11
中文摘要: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 Yamansu iron deposit in Xinjiang is hosted in the lower Carboniferous Yamansu Formation. There are volcanic rocks, carbonatite and skarns in this iron deposit. Hence, the study of the relationship of carbonate rocks and skarns to metallogenisis has important theoretical and practical significance. Based on detailed field investigation, major elements analysis, REE analysis and trace elements analysis of carbonatite, the authors investigated the geological and geochemical features of the carbonatite in the Yamansu iron ore district and its periphery. The carbonatites, containing neritic facies fossil and ooids, are distributed with volcanic rocks alternately, suggesting that the sedimentation and volcanic eruption occurred in a shallow sea environment. The types of carbonatite include micrite, finely-crystalline limestone, marble, marble with tuffaceous, calc-mylonite and calcite-tectonic-schist. Little change of main elements shows that no main components were brought in or taken out. REE and microelements also show insignificant variation, except for calcite-tectonic-schists, whose total REE and other, trace elements are lower than those of other types of carbonate rocks. This also shows that no foreign materials (including metallogenetic materials) were brought in. The calcite-tectonic-schists, being adjacent to the orebodies, were not skarnized. The authors infer that, during the process of formation and mineralization, the carbonite was only affected by structural schistosity alteration and hydrothermal recrystallization without contact metasomatism. Hence, the Yamansu iron deposit is not a skarn deposit (contact-metasomatic deposit) in the narrow sense, but a marine volcanic type deposit. The skarns in the ore district were formed by metasomatism of volcanic hydrothermal solution rather than by contact metasomatic metamorphism. The problem whether the lower carbonate formation provided rock-forming and ore-forming materials or not should be further studied.
文章编号：
中图分类号：P618.31
文献标志码：
基金项目:本文得到国家自然科学基金项目（编号：41272102）和中国地质调查项目（编号：1212010733806、12120113092700）联合资助
引用文本：
丁建华,李厚民,李立兴,陈靖,邓刚.2017.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[J].矿床地质,36(1):219~236DING JianHua,LI HouMin,LI LiXing,CHEN Jing,DENG Gang.2017.Geological and geochemical features and genetic significant of carbonatite in Yamasu iron deposit, Xinjiang[J].Mineral Deposits36(1):219~236
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