铀矿地质2025，Vol.41Issue(6)：1007-1022,16.DOI:10.3969/j.issn.1000-0658.2025.41.070
粤北青嶂山岩体江头矿区辉绿岩脉锆石U-Pb年代学、地球化学特征及其构造意义
Zircon U-Pb Geochronology,Geochemical Characteristics and Tectonic Significance of Diabase Dikes in Jiangtou Area of Qingzhangshan Pluton,Northern Guangdong
摘要
Abstract
Jiangtou area is situated in the northern part of Qingzhangshan pluton and the source of granitic uranium deposits in northern Guangdong.However,insufficient research on this area left controversies persisting regarding to its chronology,petrogenesis,and tectonic setting.Accurate dating of intermediate-basic dykes is an important prerequisite for investigating their tectonic background of formation and deep-Earth dynamics,this study systematically conducts petrography,petrogeochemistry,zircon U-Pb chronology,and zircon Hf isotope studies with the diabase in Jiangtou area.The diabase in the Jiangtou area was found rich in elements such as Rb,U,Ta,and Pb,depleted in elements such as Ba,Sr,Zr,and Hf,no significant negative anomalies in Nb,Ta,and Ti,and its low Th/Ta,Zr/Hf,and La/Sm ratios,indicating that it has barely undergone crustal contamination.In addition,the diabase has relatively low Mg#,Cr,and Ni values,indicating that fractional crystallization occurred during the magmatic process.The zircon εHf(t)values of the diabase in the Jiangtou area range from-10.6 to-7.3,with tDM2 of 1 698 to 1 907 Ma.Combined with the whole-rock geochemical characteristics,the diabase was considered to be originated from an enriched mantle.Zircon U-Pb age of the diabase in Jiangtou area is 230.2 Ma±2.0 Ma,which fall to the Indosinian period(Middle Triassic)and is consistent with the age of Qingzhangshan granite reported by previous researchers,suggesting that they are the products of the same magmatic event.Combining with the result of the geological,petrochemical and chronological data from previous studies,we concluded that Jiangtou area was in an intraplate extensional environment during Indosinian period(Middle Triassic).关键词
锆石U-Pb年龄/地球化学/锆石Hf同位素/青嶂山岩体/江头矿区Key words
zircon U-Pb dating/geochemistry/zircon Hf isotope/Qingzhangshan pluton/Jiangtou area分类
地质学引用本文复制引用
杨戬..粤北青嶂山岩体江头矿区辉绿岩脉锆石U-Pb年代学、地球化学特征及其构造意义[J].铀矿地质,2025,41(6):1007-1022,16.基金项目
广东省铀资源勘查专项资金(编号:粤铀专[2024]-2)资助. （编号:粤铀专[2024]-2）
