扬子地台西缘康滇克拉通中碎屑锆石的LA-ICP-MS U-Pb定年及其地质意义  

DETRITAL ZIRCON U-Pb DATING BY LA-ICP-MS AND ITS GEOLOGICAL SIGNIFICANCE IN WESTERN MARGIN OF YANGTZE TERRANE

作　　者：朱华平[1] 周邦国[1] 王生伟[1] 罗茂金[1] 廖震文[1] 郭阳[1] 

机构地区：[1]中国地质调查局成都地质调查中心,四川成都610081

出　　处：《矿物岩石》2011年第1期70-74,共5页Mineralogy and Petrology

基　　金：中国地质调查局国土资源调查项目(1212010813066)

摘　　要：对扬子地台西缘康滇克拉通望厂组沉积砾岩中碎屑锆石的LA-ICP-MS U-Pb定年,结果发现年龄的分布范围较大,最年轻一组碎屑锆石的207Pb/206Pb加权平均年龄为(1 838±10)Ma,为望厂组最大的沉积时限。相对集中分布的锆石测试点207Pb/206Pb加权平均年龄为(2 855±14)Ma,指示着扬子地台西缘存在着28×108年左右的陆壳。最老锆石测试点207Pb/206Pb年龄可达37.8×108年左右,是迄今为止在扬子地台西缘发现的最古老单颗粒锆石,表明在东川地区可能还存在更古老的陆壳。Based on the study of the U-Pb dating of detrital zircon by LA-ICP-MS from sedimentary conglomerate in the Wangchang Formation of Kangdian craton in western margin of Yangtze terrane,it is showed that the age scale interval of zircon points distributing along the concordant plots are wide.The youngest 207Pb/206Pb concordant age is（1 838±10） Ma,which represents the oldest sedimentary age of the Wangchang Formation.The points relatively concentrating along the concordant plots are（2 855±14） Ma,indicating that an older crust of 2.8 billion Ms occurred in western margin of Yangtze terrane.The oldest 207Pb/206Pb age is 3.78 billion,which is the oldest single particle zircon in western margin of Yangtze terrane up to now,also indicates the older crust existing in Dongchuan area.

关 键 词：扬子地台西缘 碎屑锆石 LA-ICP-MS U-PB测年 望厂组 

分 类 号：P597.3[天文地球—地球化学] P588.345[天文地球—地质学]