冀东迁滦地区沉积变质型铁矿床变质作用程度:来自石榴子石的制约  

Constrains of Garnets on the Metamorphic Degree of Sedimentary Metamorphic Iron Deposit in the Qianan-Luan Area,East Hebei Province

作　　者：张龙飞[1] 许英霞[1] 高孝敏[2] 李厚民[3] 李立兴[3] 贾东锁[2] 

机构地区：[1]河北联合大学矿业工程学院地质系,河北唐山063000 [2]河北省地矿局第二地质大队,河北唐山063000 [3]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,北京100037

出　　处：《地质与勘探》2014年第5期938-946,共9页Geology and Exploration

基　　金：国土资源部公益性行业科研项目:冀东地区沉积变质型铁矿富矿控矿条件及科学基地研究(201111002-04)资助

摘　　要：石榴子石是冀东地区沉积变质铁矿中常见的变质矿物之一。本文采集迁安-滦县地区代表性铁矿中含有石榴子石的岩石样品,对其石榴子石进行电子探针和X-射线粉晶衍射分析,得出司马地区为角闪岩相,杏山-黄柏峪一带为角闪岩-麻粒岩相,水厂-大石河地区为麻粒岩相,这与前人对迁滦地区用主要矿物共生组合等来研究变质相的结论相一致;同时迁滦地区沉积变质铁矿中石榴子石的端元组分和晶胞参数a0随变质程度的增加呈规律性变化:司马地区的铁铝榴石+钙铝榴石→杏山-黄柏峪一带的铁铝榴石→水厂-大石河一带铁铝榴石+镁铝榴石,其晶胞参数a0值逐渐减小。因此在沉积变质型铁矿床中,变质矿物石榴子石的化学成分及晶胞参数特征对不同地区的变质程度具有示踪意义。Garnet is one of the common metamorphic minerals in sedimentary metamorphic iron deposits of eastern Hebei. This work collected garnetbearing samples from typical iron deposits in the Qianan-Luan area to carry out electron microprobe analysis(EMPA) and X-ray powder diffraction analysis. The results show that the Sima area belongs to amphibolite facies,the Xingshan-Huangbaiyu belt belongs to amphibolite-granulite facies and Shuichang-Dashihe belt belongs to granulite facies. It is consistent with the previously determined metamorphic facies by analysis of paragenetic assemblage of primary minerals. In addition,end member components and unit cell parameters(a0) of garnets from sedimentary metamorphic iron deposits in the Qianan-Luan area regularly changes with the elevated degree of metamorphism: from almandite and grossularite in the Sima area to almandite in Xingshan-Huangbaiyu belt,to almandite and pyrope in Shuichang-Dashihe belt,as well as the unit cell parameters( a0) values decrease. Therefore,it is of great significance to study the chemical composition and unit cell parameters of the metamorphic mineral garnet,as it has indication meanings for metamorphic degrees of different regions.

关 键 词：石榴子石 沉积变质型铁矿床 变质程度 晶胞参数 冀东 

分 类 号：P618.31[天文地球—矿床学]