桂西那坡百都辉绿岩年代学及地球化学特征:峨眉山大火成岩省基性岩浆活动的证据  

Geochemical and chronological characteristics of diabase in Baidu of Napo, western Guangxi:the magmatic activity at the outer zone of Emeishan large igneous province

作　　者：李锦诚[1] 周旭霞 韦永先[1] 梁秋明[1] 李政林[2] LI Jin-cheng;ZHOU Xu-xia;WEI Yong-xian;LIANG Qiu-ming;LI Zheng-lin(Regional Geological Survey Research Institute of Guangxi Autonomous Region, Guilin 541003,China;College of Earth Sciences, Guilin University of Technology, Guilin 541006,China)

机构地区：[1]广西区域地质调查研究院,广西桂林541003 [2]桂林理工大学地球科学学院,广西桂林541006

出　　处：《桂林理工大学学报》2019年第2期282-290,共9页Journal of Guilin University of Technology

基　　金：国家自然科学基金项目(41463002);广西国土资源厅广西找矿突破战略行动地质矿产勘查项目

摘　　要：为探讨右江盆地西南缘基性岩浆成因,对桂西那坡县百都乡一带基性侵入岩进行了主量元素、微量元素及锆石U-Pb年龄测定分析,结果表明,岩石属于碱性系列、钙碱性玄武岩系列,稀土元素总含量变化大(∑REE=(57.20~321.26)×10-6),球粒陨石标准化稀土元素配分曲线图中配分曲线平缓右倾,(La/Yb)N=1.86~9.00,δEu=0.86~1.49,可能源自亏损地幔并受到少量地壳物质的混染作用,显示出大陆板内玄武岩的特征,弄江岩体、规腰岩体、那全岩体LA-ICP-MS锆石U-Pb年龄分别为260.5±0.9 Ma、262.5±4.9 Ma、257.4±2.6 Ma,应为峨眉山大火成岩省岩浆活动的产物。右江盆地西南缘晚二叠世处于活动陆缘构造环境,峨眉山大火成岩省岩浆沿区域性大断裂侵位。To reveal the genesis of mafic magmatic rock in the southwest margin of Youjiang basin, major and trace elements abundances are tested, and the determination of zircon U-Pb age of the diabase at Baidu area of Napo County. The result showed that the diabase are alkali, high ptassium calc-alkali, basaltic series, and the ∑REE content varies greatly(57.20-321.26)×10-6. The distribution curve of the normalized REE in the chondritic meteorite is smooth to the right,(La/Yb)N=1.86-9.00,δEu=0.86-1.49.It is believed that they were probably derived from depleted mantle with minor crust material contamination and belonged to continental intraplate basalts.The zirconia LA-ICP-MS U-Pb ages were 260.5±0.9 Ma, 262.5±4.9 Ma, 257.4 ±2.6 Ma. Therefore, it should be the products of Emeishan large igneous province. The late Permian in the southwest margin of Youjiang basin is in the active continental margin tectonic setting, the magma invades along the regional large faults in Emeishan large Igneous province.

关 键 词：辉绿岩 地球化学 那坡 右江盆地 峨眉山大火成岩省 

分 类 号：P588.124[天文地球—岩石学]