新疆磁海铁矿床Fe-O-S同位素和元素地球化学示踪

发布时间：2018-04-15 13:53

本文选题：Fe-O-S同位素 + 主/微量元素　；参考：《地质通报》2017年06期

【摘要】：新疆磁海铁矿位于北山构造-成矿带西端,以磁海矿段为主要组成部分,铁矿体主要为透镜状、似层状,围岩以辉绿岩为主,二者接触线截然且平直;另外一种矿体产在基性岩体与地层接触带的石榴子石透辉石矽卡岩岩体内,整个矽卡岩岩体即为铁矿体。通过野外矿床特征与矿相学研究,成矿过程可分为:(1)矿浆期,以磁铁矿+单斜辉石+普通角闪石的近同时产出为特征;(2)矽卡岩期,先期以石榴子石+透辉石+磁铁矿为特征,后期以透闪石/阳起石+石英+磁黄铁矿+黄铜矿+黄铁矿的组合为特征。通过对矿浆期及矽卡岩期典型矿物的地球化学及Fe、S、O同位素结果分析,认为矿浆期铁质具有幔源特征,矽卡岩期成矿流体对矿浆期具有继承性。通过与前人研究结果对比分析,认为磁海成矿可能形成于塔里木地区二叠纪地幔柱背景,含矿母岩浆可能为地幔柱的分支。
[Abstract]:The maghai iron deposit in Xinjiang is located at the western end of the Beishan tectonic-metallogenic belt with the maghai ore segment as the main component. The iron ore body is mainly lenticular and bedded, and the surrounding rock is dominated by diabase. The contact lines between them are straight and straight.Another type of orebody occurs in the garnet diopside skarn in the contact zone between the basic rock body and the strata, and the whole skarn body is an iron ore body.Based on the field study of ore deposit characteristics and mineralogy, the metallogenic process can be divided into two stages: 1) magma stage, 2) skarn stage, and 2) skarn stage, and 1) garnet diopside magnetite stage, which is characterized by magnetite monopyroxene common hornblende.The late stage is characterized by the combination of tremolite / actinite quartz pyrrhotite chalcopyrite.Based on the geochemistry of typical minerals in magma period and skarn stage and the analysis of Fe ~ (2 +) S _ (O) isotopic results, it is concluded that the iron in the pulp stage has the characteristics of mantle source, and the ore-forming fluid in skarn stage is inherited to the pulp period.By comparing and analyzing the results of previous studies, it is concluded that the magnetospheric mineralization may have been formed in the Permian mantle plume setting in the Tarim area, and that the ore-bearing parent magma may be a branch of the mantle plume.
【作者单位】：地质过程与矿产资源国家重点实验室/中国地质大学(北京)地球科学与资源学院;中国地质科学院地质研究所/国土资源部同位素地质重点实验室;
【基金】：国家自然科学基金项目《西天山Almalyk和吐拉苏矿集区成矿作用对比研究》(批准号:U1303292)、《沙漠-草原覆盖区矿产综合预测理论与隐伏矿床含矿信息提取方法》(批准号:41430320)
【分类号】：P59;P618.31

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