现代地质2024，Vol.38Issue(4)：959-976,18.DOI:10.19657/j.geoscience.1000-8527.2024.095
赣南加里东期重稀土矿赋矿母岩岩石成因及地质意义
Petrogenesis and Geological Significance of the Caledonian Heavy Rare Earth Ore Parent Rock in Southern Jiangxi Province
摘要
Abstract
Many studies have been conducted to investigate the Yanshanian heavy rare earth ore-bearing parent rocks,however only a few reports concern the Caledonian ore-bearing parent rocks.In this study,we analyzed the geochemistry,zircon U-Pb geochronology,Lu-Hf and Sr-Nd isotopes of the biotite monzonitic granites in the Caledonian Sunwu pluton in Southern Jiangxi Province.The rock samples show a SiO2 content of 69.7％-73.0％,a K2O/Na2O ratio of 1.38-2.20,and an A/CNK ratio of 1.20-1.67,belonging to the high-silicon and high-potassium-calcium alkaline-potassium basaltic S-type granite.The rock samples are relatively enriched in light rare earths((La/Yb)N=6.78-10.38)and show moderate negative europium anomalies(δEu=0.43-0.63).The weighted average ages of zircon 206Pb/238U in the two granites are(451±3.8)Ma and(461±5.6)Ma,respectively,belonging to the Middle Ordovician Epoch.The crustal model age(TDMC)for Hf iso-tope of zircon is 1918-1496 Ma,and for the whole rock is 1.79-1.76 Ga.The magma source area is mainly composed of Mesoproterozoic lower crust granulite facies source rocks,and the rock mass is intraplate granite formed during the Early Caledonian intracontinental orogeny in South China.The weathering of rare earth ele-ment-bearing minerals in the Sunwu pluton can form ion-adsorption heavy rare earth deposits.The Caledonian granite should be given sufficient attention in future exploration work for heavy rare earth elements.The re-search results provide a reference for the exploration of ion-adsorbed rare earth deposits in the weathering crust of Caledonian granite.关键词
二长花岗岩/U-Pb定年/Lu-Hf同位素/Sr-Nd同位素/孙屋岩体/离子吸附型稀土矿Key words
monzonitic granite/U-Pb dating/Lu-Hf isotope/Sr-Nd isotope/Sunwu pluton/ion-adsorbed rare earth ore分类
天文与地球科学引用本文复制引用
张德富,王先广,何涛,曹明轩,吕婷婷,龚良信,徐进..赣南加里东期重稀土矿赋矿母岩岩石成因及地质意义[J].现代地质,2024,38(4):959-976,18.基金项目
江西省安远县石头坪离子型中重稀土成矿作用及绿色采选技术试验项目(20220014) （20220014）
江西省自然资源厅科技创新项目(ZRKJ20232411,ZRKJ20232526) （ZRKJ20232411,ZRKJ20232526）
自然资源部离子型稀土资源与环境重点实验室开放基金课题(2022IRERE101,2022IRERE103). （2022IRERE101,2022IRERE103）
