东昆仑造山带白日其利辉长岩体LA-ICP-MS锆石U-Pb年龄及地质意义  

Zircon LA-ICP-MS U-Pb dating of Bairiqili gabbro pluton in East Kunlun orogenic belt and its geological significance

作　　者：熊富浩[1] 马昌前[1,2] 张金阳[3] 刘彬[1] 蒋红安[1] 黄坚[1] 

机构地区：[1]中国地质大学地球科学学院,湖北武汉430074 [2]中国地质大学/地质过程与矿产资源国家重点实验室,湖北武汉430074 [3]中国地质大学资源学院,湖北武汉430074

出　　处：《地质通报》2011年第8期1196-1202,共7页Geological Bulletin of China

基　　金：中国地质调查局计划项目<青藏高原大陆动力学及资源环境效应之工作13>(编号:1212010918002)

摘　　要：东昆仑中段的白日其利基性岩体由橄榄辉长岩、斜长岩和角闪辉长岩组成。主体岩相角闪辉长岩的锆石LA-ICP-MSU-Pb年龄表明,其侵位于248.9Ma±4.2Ma,为早三叠世阿尼玛卿古特提斯洋关闭过程中的岩浆活动。结合前人的研究,认为东昆仑造山带中生代岩浆混合作用至少始于早三叠世,白日其利岩体为研究俯冲阶段岩浆混合作用提供了窗口。同时,白日其利辉长岩中大量继承锆石的年龄表明,东昆仑基底经历了前寒武纪多旋回多期次的构造热事件,其中新发现的2109～2310Ma的古老年龄指示东昆仑在古元古代时期还存在一期岩浆热事件,其地质意义有待进一步研究。Located in the middle of East Kunlun,the Bairiqili gabbro pluton consists of olivine gabbro,anorthosite and amphibolite gabbro.LA-ICP-MS zircon U-Pb dating suggests that the main facies hornblende gabbro intruded at 248.9 ± 4.2 Ma,being part of the Early Triassic magmatism during Paleo-Tethys ocean subduction.Based on previous researches,the authors hold that the Mesozoic magma mixing in the East Kunlun orogenic belt started at least in Early Triassic,and that the Bairiqili pluton provides a window for the study of magma mixing at the subduction stage in East Kunlun.Meanwhile,a large number of inherited zircon ages indicate that East Kunlun basement underwent multi-stage and polycyclic tectono-magma event in Precambrian,and the newly-discovered old age of 2109 ～ 2310 Ma may suggest that there existed another magmatic event in Early Proterozoic,whose geological significance deserves further researches.

关 键 词：东昆仑造山带 白日其利岩体 辉长岩 LA-ICP-MS锆石U-PB年龄 前寒武纪地质 

分 类 号：P588.124[天文地球—岩石学] P597.3[天文地球—地质学]