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
梁任鑫 1时毓 1庞超伟 1刘希军1
作者信息
- 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;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
- 折叠
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.
Abstract
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Key words
Early Paleozoic tectonic events/amphibolites/zircon geochronology/geochemistry/petrology/Southeastern Guangxi引用本文复制引用
基金项目
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)
出版年
2024
国家科技期刊平台
NSTL
万方数据