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。
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
Abstract: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.
Key words:North China Craton/
BIF iron ore/
Houqiu Group/
Meta-volcanic rocks/
Zircon/
U-Pb ages
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