华北克拉通东南缘BIF型铁矿变质火山岩夹层锆石U-Pb年龄及其对铁矿形成时限的制约  

Zircon U-Pb ages of metamorphic volcanic interlayer in the BIF type iron ore at the southeastern margin of the North China Craton and their constraints on the formation time of iron ore

作　　者：王翔[1,2] 马昌前[1] 邓佳良[2] Wang Xiang;Ma Changqian;Deng Jialiang(State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Sciences,China University of Geosciences,Wuhan 430074;Geological Survey of Anhui Province(Anhui Institute of Geological Sciences),Hefei 230001)

机构地区：[1]中国地质大学(武汉)地质过程与矿产资源国家重点实验室,武汉430074 [2]安徽省地质调查院(安徽省地质科学研究所),合肥230001

出　　处：《地质科学》2021年第3期951-971,共21页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：安徽省国土科技项目(编号:2009-K-23)资助。

摘　　要：霍邱BIF型铁矿位于华北克拉通东南缘,矿体均赋存于晚太古代霍邱岩群内,主要呈似层状,与围岩产状基本一致,界线较清晰,受地层层位控制明显,为典型的层控型矿床。本次工作采集霍邱铁矿周集铁矿床ZK2918、ZK2512两处钻孔中石英磁铁矿矿体内英安质片麻岩夹层。对片麻岩类的岩石学特征、原岩性质及同位素地质年代学等进行的研究表明,英安质片麻岩类的原岩为安山质火山岩,成岩年龄分别为2 750±15 Ma,2 740±7.2 Ma;表明在华北克拉通东南缘霍邱地区存在着~2.75 Ga的岩浆活动。此外,受变质火山岩年龄制约,霍邱岩群及赋存于其中的BIF铁矿的形成时代也应为~2.75 Ga。Huoqiu BIF type iron ore deposit is located in the southeast margin of North China Craton. The ore bodies are all hosted in the late Archean Huoqiu rock group. The ore body is mainly stratoid,basically consistent with the occurrence of surrounding rocks with clear boundary, and obviously controlled by stratigraphic horizon, which is a typical strata bound type deposit. In this work, the intercalation of felsic gneiss in quartz magnetic ore body is collected from ZK2918, ZK2512 of Zhouji iron deposit of Huoqiu iron mine. The study on the petrological characteristics, protolith properties and isotopic geochronology of gneisses shows that the protoliths of felsic gneiss are andesite volcanic rocks with crystallization ages of 2 750±15 Ma, and 2 740±7.2 Ma respectively,indicating that~2.75 Ga magmatic activity exists in Huoqiu area, southeast margin of North China Craton. In addition, restricted by the age of metamorphic volcanic rocks, the formation age of Huoqiu group and the hosted BIF iron ore should be~2.75 Ga.

关 键 词：华北克拉通 BIF铁矿 霍邱岩群 变质火山岩 锆石U-PB年龄 

分 类 号：P597[天文地球—地球化学] P618.31[天文地球—地质学]