内蒙古红山子复式岩体地质时代的厘定及其地质意义  

The definition and geological significance of Hongshanzi complex rock in Inner Mongolia

作　　者：祝洪涛[1] 吴仁贵[2] 姜山[1] 巫建华[2,3] 刘洋[1] 赵博[1] 王常东[1] ZHU Hong-tao;WU Ren-gui;JIANG Shan;WU Jian-hua;LIU Yang;ZHAO Bo;WANG Chang-dong(No. 243 Geological Party,China National Nuclear Corporation,Chifeng 024000,China;School of Earth Science,East China University of Technology,Nanchang 330013,China;State Key Laboratory of Nuclear Resources and Environment,East China Universityof Technology,Nanchang 330013,China)

机构地区：[1]核工业二四三大队,内蒙古赤峰024000 [2]东华理工大学地球科学学院,江西南昌330013 [3]核资源与环境国家重点实验室(东华理工大学),江西南昌330013

出　　处：《岩石矿物学杂志》2019年第4期453-464,共12页Acta Petrologica et Mineralogica

基　　金：中国地质调查局矿产地质调查专项(DD20160136);中国核工业地质局铀矿地质勘查项目(2018-01)~~

摘　　要：通过岩相学研究和LA-ICP-MS锆石U-Pb测年,对红山子岩体的主要侵入期次和侵入岩形成时代进行了厘定,明确了红山子岩体为复式岩体并探讨了其地质意义。岩相学研究表明,红山子复式岩体由粗粒碱长花岗岩、斑状黑云母花岗岩、细粒黑云母碱长花岗岩和花岗斑岩等组成;LA-ICP-MS锆石U-Pb测年结果显示:粗粒碱长花岗岩的年龄为153. 6±1.2 Ma,斑状黑云母花岗岩年龄为151. 4±1.1 Ma,与周边火山盆地赋矿火山岩的年龄一致,属晚侏罗世早期;细粒黑云母碱长花岗岩的年龄为131. 5±1. 8 Ma,花岗斑岩年龄为133. 3±1. 4 Ma,与侵入红山子盆地的花岗斑岩的年龄一致,属早白垩世早期。因此,红山子岩体是由燕山期2个相隔20 Ma的不同期次侵入体组成的复式岩体。研究表明,红山子铀矿床赋存在早白垩世早期花岗斑岩与晚侏罗世火山岩的内、外接触带中,暗示复式岩体早白垩世早期细粒黑云母花岗岩、花岗斑岩与晚侏罗世粗粒碱长花岗岩、斑状黑云母花岗岩的内、外接触带是有利的找矿部位,并得到了铀矿勘查实践的初步证实。Through the study of lithology and LA-ICP-MS zircon U-Pb dating, the main invasion period of Hongshanzi rock and the age of intrusive rock formation were determined. It is clear that Hongshanzi rock is a complex rock. The authors discussed its geological significance. The study of petrography indicates that Hongshanzi complex rock is composed of middle coarse grained alkali feldspar granite, porphyritic biotite granite, finebiotite granite and granite porphyry. The LA-ICP-MS zircon U-Pb dating results show that the age is 153. 6 ± 1. 2 Ma for middle coarse grained alkali feldspar granite, and 151. 4 ± 1. 1 Ma for porphyritic biotite granite, which are in accordance with the data obtained around the ore-bearing volcanic basin, and belong to the early period of Late Jurassic. The age of finebiotite granite is 131. 5 ± 1. 8 Ma and that of granite porphyry is 133. 3 ± 1. 4 Ma, consistent with the age of the granite porphyry which invaded Hongshanzi Basin and belonging to the early period of Early Cretaceous. Therefore,Hongshanzi Yanshanian complex rock is composed of two different periods in Yanshanian epoch, whose time span is20 Ma. Studies show that the Hongshanzi uranium ore deposit occurs along the contact zone of granite porphyry of early Early Cretaceous and volcanic rocks of Late Jurassic, which indicates that the contact zone between complex rock of middle coarse grained alkali feldspar granite, porphyritic biotite granite and fine biotite granite and granite porphyry is the best place for mineral exploration, and this conclusion was verified by the uranium ore exploration.

关 键 词：红山子复式岩体 LA-ICP-MS锆石U-PB年龄 晚侏罗世早期 早白垩世早期 地质意义 

分 类 号：P597.3[天文地球—地球化学]