大别造山带木子店条带状铁建造的形成时代与成因初探  

Preliminary study on age and genesis of Muzidian banded ironformation in the Dabie Orogen

作　　者：黎方云 张欣[3] 费雯丽 郭盼 罗华 万俊 刘成新 孔令耀 邓新[4] Li Fangyun;Zhang Xin;Fei Wenli;Guo Pan;Luo Hua;Wan Jun;Liu Chengxin;Kong Lingyao;Deng Xin(Hubei Geological Survey,Wuhan,Hubei 430034;Hubei Key Laboratory of Resources and Eco-environment Geology,Wuhan,Hubei 430034;Harbin Center for Integrated Natural Resources Survey,China Geological Survey,Harbin,Heilongjiang 150081;Wuhan Center of China Geological Survey,Wuhan,Hubei 430205)

机构地区：[1]湖北省地质调查院,湖北武汉430034 [2]资源与生态环境地质湖北省重点实验室,湖北武汉430034 [3]中国地质调查局哈尔滨自然资源综合调查中心,黑龙江哈尔滨150081 [4]中国地质调查局武汉地质调查中心,湖北武汉430205

出　　处：《资源环境与工程》2024年第4期361-372,共12页Resources Environment & Engineering

基　　金：中国地质调查局地质调查项目(DD20190050);湖北省地质局科技项目(KJ2024-14)。

摘　　要：大别造山带木子店地区多处出露条带状铁建造(BIF),其形成时代和成因长期以来缺乏有力证据支撑。在对木子店地区王家畈、柳子冲木子店岩组剖面开展详细调查的基础上,采集代表性石榴角闪黑云斜长片麻岩、斜长角闪岩和磁铁石英岩样品,进行锆石U-Pb年代学和岩石地球化学研究,探索木子店BIF的形成时代和成因。结果表明,石榴角闪黑云斜长片麻岩和斜长角闪岩的成岩年龄分别为(2450±10)Ma、(2469±17)Ma,后者锆石中还记录了(1957±11)Ma的变质年龄;磁铁石英岩样品具有低Al_(2)O_(3)、TiO_(2)、Na_(2)O、K_(2)O,低Zr、Th、Nb、REE和高Y/Ho比值特征,在相关成因判别图解中显示其形成过程中基本无陆源碎屑物质的供给,而有高温热液的参与。结合前人资料认为木子店BIF形成于新太古代晚期—古元古代早期,基本不含陆缘碎屑物质、有高温热液参与的含铁化学沉积作用之下,属典型的阿尔戈马型BIF。The banded iron formation(BIF)is widely exposed in Muzidian area of Dabie Orogen,and its formation age and genesis have long lacked strong evidence support.Based on the detailed survey on Muzidian Formation sections in Wangjiafan and Liuzichong of Muzidian area,representative samples of garnet-amphibole-biotite-plagioclase gneiss,plagioamphibolite and magnetite-quartzite were collected to study zircon U-Pb geochronology and rock geochemistry,and to explore the formation age and genesis of Muzidian BIF.The results show that the diagenetic ages of garnet-amphibole-biotite-plagioclase gneiss and plagioamphibolite are(2450±10)Ma and(2469±17)Ma,respectively,the metamorphic age of(1957±11)Ma is also recorded in the zircon of plagioamphibolite.The magnetite-quartzite samples have the characteristics of low Al_(2)O_(3),TiO_(2),Na_(2)O,K_(2)O,low Zr,Th,Nb,REE and high Y/Ho ratio,and in the relevant genetic discrimination diagram,it shows that there is basically no supply of terrigenous clastic materials,but the participation of high-temperature hydrothermal fluid.Combined with previous data,it is believed that the Muzidian BIF was formed in the late Neoarchean-early Paleoproterozoic,and was formed by iron-bearing chemical deposition with high-temperature hydrothermal participation and basically no terrigenous clastic materials.The Muzidian BIF is a typical Algoma-type BIF.

关 键 词：木子店 条带状铁建造 锆石U-PB年龄 阿尔戈马型 大别造山带 

分 类 号：P588.242[天文地球—岩石学]