龙江盆地中生代火山岩锆石U-Pb年代学及其对基底性质的制约  

U-Pb Chronology of Mesozoic Volcanic Rocks from Longjiang Basin and Their Constraints on Basement

作　　者：张超[1,2] 吴新伟[1,2] 张渝金[1,2] 郭威[1,2] 权京玉[3] Zhang Chao;Wu Xinwei;Zhang Yujin;Guo Wei;Quan Jingyu(Shenyang Center of Geological Survery,CGS,Shenyang 110034,China;College of Earth Sciences,Jilin University tChangchun 130061,China;Shenyang Test Research,Northeast China Coal Field Geological Bureau Shenyang 110016,China)

机构地区：[1]中国地质调查局沈阳地质调查中心,沈阳110034 [2]吉林大学地球科学学院,长春130061 [3]东北煤田地质局沈阳测试研究中心,沈阳110016

出　　处：《吉林大学学报（地球科学版）》2019年第2期460-476,共17页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局项目(12120113053900;DD20160048-04;DD20160343-08;DD20160343-09)~~

摘　　要：龙江盆地是松辽盆地外围西部重要的火山断陷盆地之一,盆地内自下而上依次发育龙江组、光华组和甘河组火山岩。本文对龙江盆地火山岩进行了详细的锆石U-Pb年代学研究,结果显示:龙江组流纹岩、辉石英安岩、安山岩锆石U-Pb年龄分别为(129.7±2.4)、(129.0±2.3)和(125.6±1.3)Ma;光华组3个流纹岩锆石U-Pb年龄分别为(122.5±1.4)、(119.9±1.1)和(116.7±1.5)Ma;甘河组最年轻的锆石年龄为(114.3±2.9)Ma;显示盆地内火山岩浆活动的时限为129.7～114.3Ma,火山岩均为早白垩世岩浆活动的产物。同时在甘河组玄武质粗面安山岩中测到多组捕获锆石年龄,反映出晚二叠世(254 Ma)、晚石炭世(302Ma)、晚泥盆世(367Ma)、早志留世(433Ma)、古元古代(2 395Ma)、新太古代(2 523Ma)岩浆事件记录,这在一定程度上为龙江盆地存在古老结晶基底提供了证据。Longjiang basin is one of the important volcanic fault basins in the western periphery of Songliao basin.It is comprised of three volcanic units,Longjiang,Guanghua and Ganhe Formations,in ascending order.A detailed zircon U-Pb chronology was studied on the igneous rock from Longjiangbasin.The zircon U-Pb ages are(129.7±2.4)Ma,(129.0±2.3)Ma and(125.6±1.3)Ma in Longjiang Formation,(122.5±1.4)Ma,(119.9±1.1)Ma and(116.7±1.5)Ma in Guanghua Formation.The zircon U-Pb age of basaltic trachy-andesite of Ganhe Formation is(114.3±2.9)Ma,showing that the ages of volcanic rocks in Longjiang basin range from 129.7 to 114.3 Ma,corresponding to the Early Cretaceous.Many captured zircons in the basaltic trachy-andesite of Ganhe Formation reflect the record of magmatic events of Late Permian(254 Ma),Late Carboniferous(302 Ma),Late Devonian(367 Ma),Early Silurian(433 Ma),Paleoproterozoic(2 395 Ma),and Neoarchean(2 523 Ma),implying the existence of ancient crystallization basement under Longjiang basin.

关 键 词：龙江盆地 锆石U-Pb年代学:捕获锆石 火山岩 岩浆事件 

分 类 号：P597.3[天文地球—地球化学]