摘要
辽东地区大石湖沟斑岩型铜矿床位于华北克拉通东北缘辽吉造山带内,其矿化在空间上与侵入大石湖沟花岗岩体中的闪长玢岩脉关系密切。本文首次报道了矿区闪长玢岩形成时代及其锆石成因,探讨其成矿潜力,为区域找矿提供基础理论。利用LA-ICP-MS技术对闪长玢岩锆石进行U-Pb同位素和微量元素测定。锆石U-Pb定年结果显示,锆石具有典型岩浆成因特征,闪长玢岩侵位时间为225.6~218.7 Ma,属于晚三叠世,该期岩浆活动应与矿区内一期铜矿化作用密切相关。锆石微量元素特征显示,稀土元素丰度值均较高,w(ΣREE)介于(216.3~1305.9)×10^(-6)之间,具有Ce正异常和弱的Eu负异常特征。利用Ti温度计得到锆石形成温度为568~913℃,氧逸度范围为ΔFMQ-0.05~ΔFMQ+4.05,其氧逸度特征指示岩体具有良好的斑岩型铜矿成矿潜力。区域地质背景和锆石微量元素特征表明,该期岩浆活动可能与大陆深俯冲过程中板片断离,导致软流圈地幔上涌引起下地壳部分熔融有关。
The Dashihugou porphyry copper deposit in eastern Liaoning Province is located in the Liao-Ji orogenic belt at the northeastern margin of the North China craton,and its mineralization is spatially closely related to the diorite porphyrite veins intruded into Dashihugou granites.This paper reports for the first time the formation age of diorite porphyrite and its zircon genesis,discusses its metallogenic potential,and provides a theory for regional prospecting.Zircon U-Pb isotopes and trace elements of diorite porphyrite were determined by LA-ICP-MS.Zircon U-Pb dating results show that the emplacement time of diorite porphyrite is 225.6-218.7 Ma,which belongs to the Late Triassic.The study indicates that the magmatic activity of this period is closely related to the first stage of copper mineralization at the same time.Zircons have a typical magmatic origin,and trace elements have characteristic of high REE abundance values withΣREE content of(216.3-1305.9)×10^(-6).Meanwhile,zircons have positive Ce anomaly and weak negative Eu anomaly.The formation temperature of zircons is 568-913℃using Ti thermometer and the oxygen fugidity ranged fromΔFMQ-0.05 toΔFMQ+4.05,which indicates that the granite has metallogenic potential of porphyry-type copper deposit.Combined with the regional geological tectonic history and zircon trace element characteristics,the magmatic activity of this period may be related to the partial melting of the lower crust caused by the upwelling of the asthenospheric mantle related to plate segment detachment during the continental deep subduction process.
作者
段雪鹏
田永飞
王宁
韩学智
王宗起
于晓飞
Duan Xuepeng;Tian Yongfei;Wang Ning;Han Xuezhi;Wang Zongqi;Yu Xiaofei(Development and Research Center,China Geological Survey,Beijing 100037,China;School of Earth Science and Resources,China University of Geosciences,Beijing 100083,China;Chemical Geological Prospecting Institute of Liaoning Province,Jinzhou 121000,Liaoning,China)
出处
《吉林大学学报（地球科学版）》
CAS
CSCD
北大核心
2023年第1期140-160,共21页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(41272052,42072049)
中国地质调查局项目(121201102000150005-08,D20221649)
关键词
锆石U-PB定年
锆石微量元素
锆石成因
闪长玢岩
大石湖沟铜矿床
辽东地区
zircon U-Pb geochronology
zircon trace element
zircon genesis
diorite-porphyrite
Dashihugou copper deposit
eastern Liaoning Province
作者简介
段雪鹏(1991—),男,博士后,主要从事岩石矿物成因方面的研究,E-mail:duanxuepeng@yeah.net
