鄂东北地区典型锰矿床锆石U-Pb年代学:对锰成矿时代的制约  

Zircon U-Pb Chronology of Typical Manganese Deposits in Northeast Hubei Province:Constraints on the Age of Manganese Mineralization

作　　者：刘锐[1] 孙唯衡 代吉祥 邹院兵 陈松 蒋之飞 刘兴平 杨振[1] LIU Rui;SUN Weiheng;DAI Jixiang;ZOU Yuanbing;CHEN Song;JIANG Zhifei;LIU Xingping;YANG Zhen(School of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China;Hubei Geological&Mining Exploration Co.,Ltd.,Wuhan 430000,Hubei,China;Sixth Geological Team of Hubei Geological Bureau,Xiaogan 432000,Hubei,China)

机构地区：[1]中国地质大学(武汉)资源学院,湖北武汉430074 [2]湖北省地质矿业开发有限责任公司,湖北武汉430000 [3]湖北省地质局第六地质大队,湖北孝感432000

出　　处：《大地构造与成矿学》2024年第6期1286-1298,I0001-I0008,共21页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41002025);中央高校基本科研业务费专项资金项目(CUGL140406);湖北省国土资源厅地质勘查基金项目(HBT-16170054-170534)联合资助。

摘　　要：鄂东北地区黄麦岭组广泛发育沉积变质型锰矿床(如鹰咀山、四方山-团山沟和孙冲等锰矿床),含锰地层为一套片岩和大理岩组合,目前这些变质岩原岩的形成时代还不清楚。锰矿床赋矿地层沉积时代的确定对于该类矿床的成因研究有重要意义。本文对该区鹰咀山和团山沟锰矿床中的5件变(火山)沉积岩样品进行了LA-ICP-MS锆石U-Pb定年。结果表明,鹰咀山锰矿床2件含锰变沉积岩样品(绿泥石石英片岩17YZS04和硅质大理岩16YZS05)中最年轻的碎屑锆石年龄为687 Ma,代表了该区黄麦岭组的最大沉积年龄;团山沟锰矿床含锰变火山岩夹层中的绿片岩(TCK1-02)获得~650 Ma的原岩形成年龄,表明鄂东北地区锰沉积作用时间为~650 Ma。鹰咀山4件变沉积岩样品中碎屑锆石年龄峰值集中于0.68~0.80 Ga、~1.97 Ga和~2.45 Ga,表明黄麦岭组沉积物源主要为古元古代和新元古代物质。年龄对比研究显示,大悟-红安地区在新元古代应为扬子克拉通的一部分,扬子北缘也可能广泛发育古元古代基底。鄂东北地区锰矿成矿时代(~650 Ma)与扬子东南缘湘黔渝地区新元古代大规模锰成矿作用时间几乎一致,表明前者亦可能为Sturtian-Marinoan间冰期沉积的产物。该期锰沉积事件可能与Rodinia超大陆裂解在扬子北缘形成的浅海相沉积有关。Sedimentary metamorphic manganese deposits(such as Yingzuishan,Sifangshan-Tuanshangou,and Sunchong)are widely developed in Northeast Hubei Province.The manganese-bearing strata,i.e.,the Huangmailing Formation,comprise a set of schist and marble assemblages,and the formation age of these metamorphic protoliths is still unclear.Determining of the sedimentary age of the host strata of these manganese deposits is important for studying their genesis.In this study,U-Pb ages of detrital zircon in five samples of metamorphic volcanic-sedimentary rocks from the Yingzuishan and Tuanshangou manganese deposits were determined using LA-ICP-MS method.The youngest detrital zircon from two samples of manganese-bearing metasedimentary rocks(17YZS04-chlorite-quartz schist;16YZS05-siliceous marble)was 687 Ma,representing the maximum deposition age of the Huangmaiing Formation.The protolith formation age of~650 Ma was obtained from the greenschist,an interlayer of manganese-bearing volcanic rocks,in the Tuanshangou manganese ore deposit,indicating that the manganese deposition time in Northeast Hubei is~650 Ma.The peak ages of the detrital zircons in the four Yingzuishan metasedimentary rocks are 0.68-0.80 Ga,~1.97 Ga,and~2.45 Ga,suggesting that the sources of the Huangmailing Formation sediments were mainly Paleoproterozoic and Neoproterozoic.The comparative study indicates that the Dawu-Hong’an area was part of the Yangtze Craton during the Neoproterozoic era,and the Paleoproterozoic basement may have been extensively developed on the northern margin of the Yangtze Craton.The metallogenic age of manganese deposits in Northeast Hubei(~650 Ma)is almost the same as that of the large-scale manganese mineralization in the southeastern margin of the Yangtze Craton,indicating that the former was also the product of Sturtian-Marinoan interglacial deposition.The manganese deposition event may be related to shallow-marine facies deposition in the northern margin of the Yangtze Craton during the breakup of the Rodinia supercontinent.

关 键 词：锰矿床 变(火山)沉积岩 碎屑锆石 锆石U-PB定年 鄂东北 

分 类 号：P597[天文地球—地球化学] P611[天文地球—地质学]