铀矿地质2025，Vol.41Issue(2)：314-331,18.DOI:10.3969/j.issn.1000-0658.2025.41.022
云开造山带北段侏罗纪花岗岩年代学、地球化学特征及其地质意义
Chronological,Geochemical Characteristics and Geological Significance of Jurassic Granites in the Northern Segment of Yunkai Orogenic Belt
摘要
Abstract
Nandu-Yangmei pluton is located in the northern margin of the Shuiwen Basin in the Cenxi area of southeastern Guangxi.It is the Jurassic granite in the northern segment of the Yunkai orogenic belt.The pluton is composed of Nandu granitic pluton(so-called Nandu pluton)and Yangmei granitic pluton(so-called Yang pluton).Through the study of petrology,chronology,and geochemistry of rocks,we has determined the diagenetic age,source region characteristics,and the forming tectonic setting of the pluton.The results indicates that the Nandu-Yangmei pluton is a complex which expernced systematic evolution.Nandu pluton is composed of pyroxene diorite,monzonite and syenite,and the zircon U-Pb dating by LA-ICPMS suggest the pluton was crystallized in 156.8-156.2 Ma.The Yangmei pluton is composed of monzonitic granite and late granite porphyry and crystallized in 156.3-155.3 Ma,while the late granite porphyry was formed in 152 Ma.Therefore the plutons were crystallized nearly in the same age,indicating that these plutons emplaced in the same period by diferrent phase.In terms of geochemical characteristics,Nandu pluton belongs to shoshonitic A-type granite,while Yangmei pluton belongs to calc-alkaline A-type to S-type transitional granite.Both of them have obvious differentiation of light and heavy rare earth elements,and are enriched in large ion lithophile elements and high field strength elements.However,Yangmei pluton is more enriched in rare earth elements,and the negative anomaly of Eu is more intense.Nandu pluton even has positive anomaly of Eu,indicating that the magma of Nandu pluton was participated with mantle source material,while Yangmei pluton was derived from crust melting.The Nandu pluton has the characteristics of intraplate granite,while the Yangmei pluton has the characteristics of transition from intraplate to activation.In conclusion,Yangmei-Nandu granite is a late Jurassic complex pluton formed under the conversion setting from the Tethys tectonic domain to the Pacific tectonic domain in the early and middle Jurassic.关键词
云开造山带/侏罗纪/南渡-杨梅岩体/岩石地球化学/年代学Key words
Yunkai orogenic belt/Jurassic/Nandu-Yangmei pluton/lithogeochemistry/chronology分类
地质学引用本文复制引用
崔倩倩,杨启军,黄浩峰..云开造山带北段侏罗纪花岗岩年代学、地球化学特征及其地质意义[J].铀矿地质,2025,41(2):314-331,18.基金项目
广西找矿突破项目(编号:桂核办[2019]4号)资助. （编号:桂核办[2019]4号）
