冀东杏山沉积变质型铁矿床富铁矿成因探讨  

Genesis of High-Grade Ores in the Xingshan Sedimentary Metamorphic Iron Deposit of Eastern Hebei Province

作　　者：张龙飞[1] 许英霞[1] 高孝敏[2] 贾东锁[2] 王宇[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063009 [2]河北省地矿局第二地质大队,河北唐山063000

出　　处：《地质与勘探》2015年第3期405-413,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：本文在野外勘查和岩(矿)相学基础上,对杏山铁矿块状富矿和条带状普通矿石进行主量元素、微量元素和稀土元素等系统研究。杏山铁矿石主要由磁铁矿和石英组成,其中块状富铁矿石相较于条带状普通矿石含有较多的镁铁质矿物,另外块状富矿(XS-60)手标本可见绿泥石化,但镜下蚀变程度较弱,其富矿成因与后期热液蚀变相关度不高;条带状贫矿(XS-10)遭受较强的后期热液蚀变,有一定程度的铁质富集,但仅限于富铁条带,富硅条带未蚀变。矿石中低Al2O3+Na2O含量和Zr、Sc、Th、Hf等含量特征表明杏山铁矿在沉积过程中很少有陆源碎屑加入。微量元素和稀土元素配分模式表明条带状普通矿石和块状富铁矿有共同的成矿物质来源,富铁矿和贫矿都是在缺氧环境下,通过海底热液与海水混合后同沉积形成的,而后期褶皱变形作用使贫矿层加厚的同时,也使富铁层加厚。Analyses of major,trace,and rare-earth elements were performed to the massive rich ore and the banded ore of the Xingshan iron deposit based on field work and petrographic study. The Xingshan iron ore is mainly composed of magnetite and quartz. Compared with the banded ordinary ore,the massive rich ore contains more mafic minerals. In addition,the chloritization can be found in the hand specimen of the massive rich ore( XS- 60),while the alteration under the microscope is weak. And there is low correlativity between the rich ore( XS- 60) and the later hydrothermal alteration.Meanwhile,the banded ore( XS- 10) has suffered from strong later hydrothermal alteration and a certain degree of enrichment of iron that only appears in the iron rich bands. The content of Al2O3+ Na2 O and the trace elements such as Zr,Sc,Th and Hf indicates that there is a little terrigenous debris joining the deposition process of the Xingshan iron deposit. The trace elements and REE patterns show that the massive rich ore and the banded ordinary ore have the common source of ore-forming material. After seafloor hydrothermal was mixed with seawater,both the rich iron ore and the banded ore were formed simultaneously with sedimentation in an anoxic environment. The lean ore layer and the rich iron layer were thickened by later fold deformation.

关 键 词：杏山铁矿 富铁矿 沉积变质型铁矿床 冀东 

分 类 号：P618.31[天文地球—矿床学]