青海洪水河铁矿区硅质岩岩石学、地球化学特征及地质意义  

Petrological and Geochemical Characteristics of Cherts in the Hongshuihe Fe Deposit,Qinghai and Their Geological Significances

作　　者：贾启元 吕新彪[1,2] 韦晓青[3] 毛晨[1] 高学鹏[4] 张帅[1] JIA Qi-yuan LV Xin-biao WEI Xiao-qing MAO Cheng GAO Xue-peng ZHANG Shuai(Faculty of Earth Resource, China University of Geosciences（ Wuhan ） , Wuhan 430074, China State Key Laboratory of Geological Processes and Mineral Resource, Wuhan 430074, China School of Environmental Studies, China University of Geosciences （Wuhan） , Wuhan 430074, China Geological Survey Institute, China University of Geosciences（ Wuhan）, Wuhan 430074, China)

机构地区：[1]中国地质大学(武汉)资源学院,武汉430074 [2]地质过程与矿产资源国家重点实验室,武汉430074 [3]中国地质大学(武汉)环境学院,武汉430074 [4]中国地质大学(武汉)地质调查研究院,武汉430074

出　　处：《矿物岩石地球化学通报》2016年第5期984-993,共10页Bulletin of Mineralogy, Petrology and Geochemistry

基　　金：中国地质调查局地质大调查项目(12120114018001)

摘　　要：青海洪水河铁矿区发育一套与铁矿体呈共生关系的硅质岩,为认识铁矿床的成矿作用和成因类型,对其进行了岩相学和地球化学研究。结果表明,矿区内硅质岩富集Si O2贫Fe2O3、Al2O3、Ti O2等;Cr和Zr含量较低,相对富集U而贫Th;稀土元素总量较低,重稀土弱富集,具有Eu负异常和弱Ce负异常。硅质岩是海相热水沉积成因,形成过程中有少量来自于古老地壳的陆源物质加入;硅质岩形成于海水相对较深的大陆边缘环境,沉积环境氧逸度较低。由野外产状可知,硅质岩和铁矿床是同沉积期产物,形成于相同的构造环境之中。因此,根据成矿物质源区和热液性质分析认为,洪水河铁矿床是海相热液沉积成因,形成于大陆边缘深海环境。In the Hongshuihe Fe deposit,there is a set of cherts that are closely related to the ore bodies.In order to un-derstand the mineralization and genetic types of the Fe deposit,petrographic and geochemical studies of the cherts have been conducted in this paper.The results show that the cherts are rich in SiO2 but poor in Fe2O3,Al2O3,and TiO2 for the major elements,relatively rich in U but relatively poor in Cr,Zr,and Th for the trace elements.The cherts contain relative low contents ofREE with weak enrichment of HREE,Eu negative anomalies and weak Ce negative anomalies.They are marine hydrothermal sedimentary genesis with the input of a small amount of ancient terrigenous material of earth＇s crust. They were formed in marine sedimentary environment with a low oxygen fugacity.Based on the field observation,the cherts and Fe ore bodies were simultaneously formed in the same tectonic environment.Therefore,on the view of ore-forming ma-terial source and hydrothermal fluid properties,it is believed that the Hongshuihe Fe deposit was formed through the ma-rine hydrothermal sedimentation in the continental margin deep sea environment.

关 键 词：硅质岩 岩石学 地球化学 海相热水沉积 大陆边缘 

分 类 号：P588.244[天文地球—岩石学] P618.31[天文地球—地质学]