桂东南岑溪—陆川地区斜长角闪岩的年代学、地球化学特征及其地质意义  

Geochronology,Geochemistry and Geological Significance of Amphibolites in Cenxi-Luchuan Area,Southeastern Guangxi

作　　者：梁任鑫 时毓[1,2] 庞超伟 刘希军[1,2] LIANG Renxin;SHI Yu;PANG Chaowei;LIU Xijun(Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration,Guilin University of Technology,Guilin 541004,China;Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources,Guilin University of Technology,Guilin 541004,China)

机构地区：[1]桂林理工大学广西隐伏金属矿产勘查重点实验室,桂林541004 [2]桂林理工大学有色金属矿产勘查与资源高效利用协同创新中心,桂林541004

出　　处：《高校地质学报》2024年第2期178-195,共18页Geological Journal of China Universities

基　　金：国家自然科学基金项目(42372083);广西自然科学基金杰出青年基金项目(2019GXNSFFA245005)联合资助。

摘　　要：文章对桂东南岑溪—陆川地区的斜长角闪岩进行了锆石U-Pb年代学和全岩地球化学分析,研究结果表明,研究区斜长角闪岩的形成时代不早于早古生代(487~428 Ma)。中—新太古代的古老锆石揭示该地区深部可能存在未暴露的太古代结晶基底。全岩地球化学分析显示,样品相对于原始地幔富集大离子亲石元素(LILE)如K、Rb、Ba、Sr等和轻稀土元素,明显亏损高场强元素(HFSE)如Nb、Ta、Ti等,类似于岛弧玄武岩(IAB)的特征。研究区斜长角闪岩由古老俯冲交代的地幔楔熔融而成,可能形成于早古生代碰撞后的岩石圈伸展阶段。Zircon U-Pb geochronology and whole-rock geochemistry of amphibolites in Cenxi-Luchuan area,southeastern Guangxi are analyzed in this study.The results show that the amphibolites are probably formed later than the Early Palaeozoic(487-428 Ma).The Mid-Neoarchean zircons reveal that the unexposed Archean crystalline basement might be existed.The whole-rock geochemistry shows that the amphibolites are enriched in large ion lithophile elements(LILE)such as K,Rb,Ba,Sr,etc.,and light rare earth elements relative to the original mantle.They are obviously depleted in high field strength elements(HFSE)such as Nb,Ta,Ti,etc.,similar to the characteristics of island arc basalt(IAB).The amphibolites are formed by melting the mantle wedge of ancient subduction metasomatism,which might be in the lithospheric extension stage after collision in the Early Paleozoic.

关 键 词：早古生代构造事件 斜长角闪岩 锆石年代学 地球化学 岩石学 桂东南 

分 类 号：P595[天文地球—地球化学]