西北地质2024，Vol.57Issue(6)：278-289,12.DOI:10.12401/j.nwg.2024084
豫西栾川矿集区南泥湖和石宝沟岩体锆石U-Pb-Hf-O同位素特征及地质意义
Zircon U-Pb-Hf-O Isotopic Characteristics and Geological Significance of Nannihu and Shibaogou Rock Mass in Luanchuan Ore Concentration Area,Western Henan Province
摘要
Abstract
The Luanchuan mining area is located at the southern edge of the North China Craton,which is rich in mineral resources and has produced a number of large-sized and super-large porphyry-silica type molybde-num and tungsten deposits.There are frequent magmatic activities in Late Mesozoic,forming several ore-bear-ing granite bodies and porphyry rock strains,and the controlling factors of their mineralization differences and potentials are still unclear.In this paper,we take the Mo-rich granite body of Nannihu and the ore-poor granite body of Shibaogou in the Luanchuan mining concentration area as the research objects,and based on zircon U-Pb dating and Hf-O isotope study,we reveal the age of their diagenesis and metallogeny,magma source area,and metallogeny indication significance.The zircon U-Pb ages of the Shibaogou rock and the Nannihu rock are(147.5±2.2)Ma and(139.5±1.8)Ma,respectively,and both are the products of Yanshan-age magmatism.The zircon εHf(t)values of the Shibaogou body range from-27.40～-14.51,and the two-stage mode age TDM2 val-ues range from 2.15～2.93 Ga,with δ18O values of 5.42‰ to 6.77‰.The zircon εHf(t)values of the Nannihu body range from-16.84～-8.04,with second-stage mode age TDM2 values ranging from 1.70～2.26 Ga and δ18O values of 5.88‰～8.27‰.The zircon U-Pb ages and Hf-O isotope results indicate that the source area of the Shibaogou ore-poor magma originated from partial melting of the thickened lower crust of the Qinling orogenic belt in the context of localized extensional downstretching of post-collisional orogeny;and that the Mo-rich por-phyry magma of the Nannihu is characterized by crust-mantle mixing.关键词
花岗斑岩/锆石U-Pb-Hf-O同位素/岩浆源区/栾川矿集区Key words
granite porphyry/Zircon U-Pb-Hf-O isotope/magma source region/Luanchuan ore concentra-tion area分类
天文与地球科学引用本文复制引用
陈雅鹏,唐利,胡昕凯,盛渊明,曾涛,陈龙龙,赵江林..豫西栾川矿集区南泥湖和石宝沟岩体锆石U-Pb-Hf-O同位素特征及地质意义[J].西北地质,2024,57(6):278-289,12.基金项目
科技部重点研发计划项目"大陆碰撞带岩浆演化过程成矿物质的富集机理"(YBC018004)和中国地质大学(北京)求真学人项目"秦岭造山带碳酸岩型矿床Mo-REE富集成矿机理"(590223001)联合资助. （YBC018004）
