北淮阳早白垩世金刚台组火山岩LA-ICP-MS锆石U-Pb年龄及其地质意义  

LA-ICP-MS zircon U-Pb ages of Early Cretaceous volcanic rocks from Jingangtai Formation in Beihuaiyang belt on the northern margin of the Dabie Orogen and their geological implications

作　　者：黄皓[1] 薛怀民[1] 

机构地区：[1]中国地质科学院地质研究所,北京100037

出　　处：《岩石矿物学杂志》2012年第3期371-381,共11页Acta Petrologica et Mineralogica

基　　金：深部探测技术与实验研究专项(SinoProbe-05-05);中国地质调查局地质调查项目(1212010711814);地质矿产调查评价专项(1212011121116)

摘　　要：金刚台组火山岩是大别造山带北缘北淮阳晚中生代火山岩带的重要组成部分,选取金刚台组的粗面安山岩、熔结凝灰岩以及紧邻火山岩的正长斑岩,用LA-ICP-MS锆石U-Pb法进行了年龄测定,结果显示:两个火山岩样品的年龄分别为128.8±0.7 Ma和127.6±0.5 Ma,紧邻火山岩的正长斑岩的年龄为129.8±0.7 Ma,这3组年龄值在误差范围内近于一致,说明金刚台组火山岩和紧邻火山岩的正长斑岩是在很短的时间内形成的。这些年龄与整个苏鲁-大别造山带内早白垩岩世岩浆活动年龄的峰值区间一致,可能意味着它们形成于相同的动力学条件下。The Jingangtai Formation constitutes an important component part of the Beihuaiyang Late Mesozoic volcanic rock belt. In this paper, the zircon U-Pb age of an ignimbrite sample was determined, and a trachyandesire sample from the Jingangtai Formation and an orthophyre sample collected near the volcanic rocks were dated by LA-ICP-MS method. According to the results, the ages of the 3 sample are almost identical within the error range, which means that the volcanic rocks of Jingangtai Formation and the orthophyre were formed in a very short period. Meanwhile, these ages are very close to the concentrated ages of the Cretaceous magmation in Sulu-Dahie orogen, which implies that they might have been generated under the same dynamic condition.

关 键 词：锆石年龄 金刚台组 早白垩世 北淮阳 大别造山带 

分 类 号：P588.14[天文地球—岩石学] P597.3[天文地球—地质学]