扬子板块西缘中生代—新生代碰撞造山事件的记录:来自峨眉山玄武岩的锆石U-Pb同位素证据  

Records of Mesozoic-Cenozoic Collision Orogenic Events on the Western Margin of the Yangtze Platform:Geochronology Evidence from Zircon U-Pb Isotope of Emeishan Basalt

作　　者：张宏辉 袁永盛 余杨忠 李鸿 张沥元 李致伟 郭太堂 潘江涛 詹华思 石海涛 ZHANG Honghui;YUAN Yongsheng;YU Yangzhong;LI Hong;ZHANG Liyuan;LI Zhiwei;GUO Taitang;PAN Jiangtao;ZHAN Huasi;SHI Haitao(Kunming Natural Resources Comprehensive Investigation Center of China Geological Survey,Kunming,Yunnan650100,China;Geophysical Investigation Center of China Geological Survey,Langfang,Hebei065000,China;Haikou Marine Geological Investigation Center of China Geological Survey,Haikou,Hainan571127,China;Urumqi Natural Resources Comprehensive Investigation Center of China Geological Survey,Urumqi,Xinjiang830000,China)

机构地区：[1]中国地质调查局昆明自然资源综合调查中心,云南昆明650100 [2]中国地质调查局地球物理调查中心,河北廊坊065000 [3]中国地质调查局海口海洋地质调查中心,海南海口571127 [4]中国地质调查局乌鲁木齐自然资源综合调查中心,新疆乌鲁木齐830000

出　　处：《现代地质》2021年第5期1155-1177,共23页Geoscience

基　　金：中国地质调查局项目“重要矿产资源调查评价”子项目“云南乌蒙山西部甸尾街、沧溪、马街、朵马戛幅150000区域地质矿产调查”(DD2016008001)。

摘　　要：利用LA-ICP-MS测定技术,对扬子板块西缘滇东倘甸一带的峨眉山玄武岩中的锆石进行了U-Pb同位素年龄测定,363个年龄数据的分布范围为(14.9±0.6)~(3023±50)Ma,跨越地质时代长,其11个年龄峰值为750~850 Ma、~450 Ma、~275Ma、~260 Ma、~247 Ma、~215 Ma、~160 Ma、~120 Ma、~100 Ma、~52 Ma及~35 Ma,反映了峨眉山玄武岩在形成过程中经历地壳物质的混染,形成后受到了后期构造热事件的巨大影响。其中峨眉山玄武岩一、二亚旋回分别形成于(259.9±3.2)Ma及(259.2±3.6)Ma,~275 Ma的玄武岩锆石年龄可能代表峨眉山玄武岩岩浆房的形成年龄及峨眉地幔柱事件导致地壳开始隆升的时间,峨眉山玄武岩形成后,扬子板块西缘依次经历了~247 Ma、~215 Ma、~160 Ma、~120 Ma、~100 Ma、~52 Ma、~35 Ma的构造热事件,这些年龄数据是扬子板块西缘中生代—新生代碰撞造山事件达到温压高峰的时间记录。Using LA-ICP-MS technique,the U-Pb isotope determination of zircons in the Emeishan basalts in Tangdian,of eastern Yunnan on the western margin of the Yangtze Plate is carried out.The distribution range of 363 age data is(14.9±0.6)-(3,023±50)Ma,spanning a long geological age,its 11 age peaks are 750~850 Ma,~450 Ma,~275 Ma,~260 Ma,~247 Ma,~215 Ma,~160 Ma,~120 Ma,~100 Ma,~52 Ma and~35 Ma,respectively,reflecting that Emeishan basalt experienced the contamination of crustal materials in the formation process,and being affected by later tectonic thermal events.The first and second sub-circle of the Emeishan basalt were formed at(259.9±3.2)Ma and(259.2±3.6)Ma,respectively.The zircon ages of the basalts of~275 Ma may represent the age of the formation age of Emeishan basalt magma chamber and the time when the crust began to uplift due to Emei mantle plume event.After the formation of the Emeishan basalt,the western margin of the Yangtze Plate experienced successively tectonic thermal events of~247 Ma,~215 Ma,~160 Ma,~120 Ma,~100 Ma,~52 Ma,and~35 Ma.These age data are the time records of the Mesozoic Cenozoic collision orogenic event reaching the peak of temperature and pressure on the western margin of the Yangtze Plate.

关 键 词：峨眉山玄武岩 锆石U-Pb年龄 碰撞造山 扬子板块西缘 LA-ICP-MS 

分 类 号：P542[天文地球—构造地质学] P597[天文地球—地质学]