长江铀矿田花岗岩与铀成矿年代学研究进展  

Chronological study advances of the granites and uranium mineralization in the Changjiang uranium ore-field

作　　者：朱卫平 ZHU Wei-Ping(School of Earth Science,East China University of Technology,Nanchang 330013,China;Key Laboratory of Airborne Geophysics and Remote Sensing Geology,MNR,Beijing 100083,China;China Aero Geophysical Survey and Remote Sensing Center for Natural Resources,Beijing 100083,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]自然资源部航空地球物理与遥感地质重点实验室,北京100083 [3]中国自然资源航空物探遥感中心,北京100083

出　　处：《物探与化探》2022年第6期1327-1337,共11页Geophysical and Geochemical Exploration

基　　金：中核联合基金项目(NRE2021-01);国家重点研发计划课题(2017YFC0602201、2017YFC0602106);中国地质调查局项目(121201203000160006、DD20190551)。

摘　　要：长江铀矿田位于粤北诸广山岩体中南部,因产有棉花坑(302)、书楼丘(305)和长排等众多铀矿床而著名。空间上,这些铀矿床主要沿着长江岩体和油洞岩体接触部位分布,铀成矿与长江岩体和油洞岩体及其侵入其中的岩脉关系密切。前人对长江铀矿田岩体、岩脉与矿床等的形成年龄开展了大量测试工作,获得了丰富的年龄数据。本文总结了长江铀矿田花岗岩、铀成矿及岩脉年代学研究进展,结果表明:长江黑云母花岗岩岩体形成时间为166~157 Ma(加权平均年龄为160.9 Ma),为中—晚侏罗世;油洞二云母花岗岩岩体形成于245.6~219.6 Ma(加权平均年龄为232.1 Ma),为三叠纪。区内发育辉长闪长岩、角闪辉绿岩、细粒花岗质岩和煌斑岩等多种岩脉,岩脉活动至少可以划分为3期,即晚侏罗世基性脉岩(150~145.1 Ma)、早白垩世酸性脉岩(138.6~123.9 Ma)和早白垩世基性脉岩(110 Ma)。长江铀矿田的铀成矿作用从早白垩世已经开始,一直持续到古新世,年龄数据127~60 Ma,时间跨度较大,可划分为早白垩世成矿期(127~119 Ma)、晚白垩世成矿期(75~67 Ma)和古新世成矿期(61~54 Ma),其中以70~60 Ma(晚白垩世—古新世)年龄数据比较集中,可能是该区铀成矿高峰期。从时间来看,长江铀矿田成岩与铀成矿演化顺序为:油洞岩体→长江岩体→早期基性岩脉→细粒花岗质岩脉→早期铀成矿阶段→细粒黑云母花岗岩脉→晚期基性岩脉→第二期铀成矿阶段→晚期铀成矿阶段。长江铀矿田成岩与铀成矿作用可以划分为6期:三叠纪花岗岩浆作用(油洞岩体)、中—晚侏罗世花岗岩浆作用(长江岩体)、晚侏罗世基性脉岩作用(辉长闪长岩脉,150 Ma;角闪辉绿岩脉,145 Ma)、早白垩世脉岩与铀成矿作用(138.6~110 Ma)、晚白垩世铀成矿作用(75~67 Ma)、古新世铀成矿作用(61~54 Ma)。后续建议进一步加强除棉花坑铀矿床(302)、书楼丘铀矿床(305)和长排The Changjiang uranium ore field is located in the south-central part of the Zhuguangshan pluton in northern Guangdong Province.This ore field holds many uranium deposits such as Mianhuakeng(302),Shulouqiu(305),and Changpai.These uranium deposits are mainly distributed along the contact parts between the Changjiang and Youdong plutons,and uranium mineralization is closely related to the Changjiang and Youdong plutons and their intrusive dykes.Previous researchers have conducted much testing on the formation ages of plutons,dykes,and deposits in the Changjiang ore field,obtaining abundant age data.This study summarized the chronological study advances of the granites,uranium mineralization,and dykes in the Changjiang uranium ore field.The results are as follows.The Changjiang biotite granite pluton was formed at 166~157 Ma(weighted average age:160.9 Ma)during the Middle-Late Jurassic.The Youdong two-mica granite pluton was formed at 245.6~219.6 Ma(weighted average age:232.1 Ma)during the Triassic.A variety of dykes such as gabbro diorites,hornblende diabases,fine-grained granitic rocks,and lamprophyres have developed in the study area.The dykes in the ore field can be divided into at least three categories according to their activity stages,namely Late Jurassic mafic dykes(150~145.1 Ma),Early Cretaceous acid dykes(138.6~123.9 Ma),and Early Cretaceous mafic dykes(110 Ma).The uranium mineralization of the Changjiang uranium ore field began during the Early Cretaceous and lasted until the Paleocene,showing a long time span ranging from 127 to 60 Ma.The uranium metallogenic periods include the Early Cretaceous metallogenic epoch(127~119 Ma),the Late Cretaceous metallogenic epoch(75~67 Ma),and the Paleocene metallogenic epoch(61~54 Ma).The age data are concentrated in the range of 70~60 Ma(Late Cretaceous-Paleocene),which might be the peak of uranium mineralization of the study area.The diagenesis and uranium mineralization of the Changjiang uranium ore field evolved in the order of Youdong pluton→Changjiang pluton�

关 键 词：长江铀矿田 成岩年龄 成矿年龄 成矿作用 研究进展 

分 类 号：P632[天文地球—地质矿产勘探]