冀东南山BIF铁矿床形成时代及成因探讨

发布时间：2018-01-24 00:43

本文关键词： 条带状铁建造(BIF) 成矿时代形成背景华北克拉通　出处：《中国矿业》2017年S2期 　论文类型：期刊论文

【摘要】：前寒武纪条带状铁建造(BIF)铁矿是我国最为重要的铁矿类型,冀东地区是国内重要铁矿开采基地之一。南山铁矿位于冀东迁安北部,是一大型铁矿床,也是该区最为典型的BIF铁矿。铁矿体赋存于晚太古代变质岩系中,矿体形态复杂,与斜长角闪片麻岩互层,矿石类型主要为磁铁石英岩,具有典型的条带状构造。南山铁矿体与斜长角闪片麻岩呈互层产出,表明二者在时间空间具有相关性。对斜长角闪片麻岩中的锆石进行了U-Pb定年分析,结果表明其原岩(火山岩)喷出时代为2 513.2±8.4Ma,从而推测南山铁矿形成于约2 513 Ma,随后在2 492±4 Ma受到变质作用的改造。南山铁矿原始沉积成矿的年龄为2.5Ga,与华北克拉通以及世界上的BIF铁矿成矿高峰期同时,此时期的BIF形成峰期不仅仅指示了华北克拉通的拼贴聚合,也可能与更大范围克拉通的形成有关。
[Abstract]:Precambrian banded iron formation (BIFF) iron ore is the most important iron ore type in China. Eastern Hebei is one of the most important iron ore mining bases in China. Nanshan Iron Mine is located in the northern part of Qianan, East Hebei Province, and is a large iron deposit. It is also the most typical BIF iron deposit in this area. The iron ore body occurs in the late Archean metamorphic rock series. The ore body is complex in shape and interbedded with the obliquity diorite gneiss. The ore type is mainly magnetite quartzite. Nanshan iron ore body and plagioclase diornesian gneiss are interbedded, indicating the correlation between them in time and space. U-Pb dating analysis of zircon in amphibole gneiss is carried out. The results show that the exhalation age of the source rock (volcanic rock) is 2513.2 卤8.4 Ma, which indicates that Nanshan iron deposit was formed at about 2513 Ma. Then metamorphism was carried out at 2 492 卤4 Ma. The age of primary sedimentary mineralization of Nanshan Iron Mine is 2.5 Ga, which coincides with the peak of mineralization of North China Craton and BIF iron ore in the world. The peak period of BIF in this period not only indicates the collage polymerization of North China Craton, but also may be related to the formation of a wider range of cratons.
【作者单位】：河北省地矿局第五地质大队;华北理工大学矿业工程学院地质系;
【分类号】：P618.31
【正文快照】： 0引言条带状铁建造(Banded iron formation,简称BIF)通常是指全铁含量大于15%,主要由互层的硅质条带和铁质条带组成的早前寒武纪特有的海相化学沉积岩[1]。而与BIF有关的铁矿是我国乃至世界上最重要的铁矿类型。据统计,与BIF相关的铁矿石产量占全球铁矿石产量的90%[2]。在我国

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