桂东北花山岩体年代学、岩石地球化学和硼同位素特征及其地质意义

Geochronology,Geochemistry,and Boron Isotopic Characteristics of the Huashan Granitoid in Northeastern Guangxi and Their Geological Significance

位于广西东北部的花山复式岩体是南岭地区与中生代花岗岩有关的铀-多金属成矿带的重要组成部分。文章通过详细的岩相学、地球化学、锆石U-Pb年代学和电气石硼同位素分析,探讨了花山岩体的形成时代、岩石成因和源区特征。研究结果显示,花山地区岩浆侵入活动高峰发生在中侏罗世晚期(~162 Ma),花山主体花岗岩具有高硅、富碱、高铁镁比值、贫CaO、MgO、Sr、Ba等特点,岩石成因类型属于高分异A型花岗岩。电气石原位硼同位素揭示,花山岩体的源区可能为陆壳变质沉积岩部分熔融形成,并经历了强烈的壳-幔岩浆混合作用。此外,文章还探讨了花山地区岩浆活动与铀成矿作用之间的可能联系,为理解花岗质岩浆作用与铀多金属矿化的成因关系提供了重要信息。

The Huashan granite complex in Northeast Guangxi is a very important part of Mesozoic uranium-polymetallic mineralization belt related to granitic rock in the Nanling Range.This study employs detailed petrography,geochemistry,zircon U-Pb geochronology,and tourmaline boron isotope analysis to investigate the petrogenesis and source of the Huashan pluton.The results indicated that the magmatic activities in the Huashan area peaked in the late Middle Jurassic(~162 Ma),characterized by high silica,alkali-rich composition,high iron-magnesium ratio,and low CaO,MgO,Sr,Ba,which is identified as highly differentiated A-type granite.In-situ boron isotopes in tourmaline suggest the source of the Huashan pluton were likely derived from partial melting of metamorphosed sedimentary rocks by intense crust-mantle magmatic mixing.Additionally,this study explored the potential link between Huashan magmatism and uranium mineralization,which provide significant insights into the genesis relationship between granitic magmatism and uraniumpolymetallic mineralization.