华北陆块东北缘张三沟岩组SHRIMP锆石U-Pb年代学研究及其地质意义  

Zircon SHRIMP U-Pb Geochronology of the Zhangsangou Formation Complex in the Northeastern Margin of North China Block,and Its Geological Significance

作　　者：李承东[1] 张福勤[2] 苗来成[2] 杜玉林 花艳秋[4] 许雅雯[1] 康淑梅 

机构地区：[1]天津地质矿产研究所,天津 300170 [2]中国科学院地质与地球物理研究所,北京 100029 [3]内蒙古自治区第九地质勘查院,内蒙古锡林浩特 026000 [4]吉林省区域地质矿产调查研究所,长春 130022 [5]吉林省第二地质调查所,吉林省吉林市 132001

出　　处：《地质学报》2009年第5期642-650,共9页Acta Geologica Sinica

基　　金：中国国家自然科学基金项目(编号40473030);中国科学院知识创新工程项目(编号KZCX2-104);中国地质调查局项目(编号1212010811004)资助的成果。

摘　　要：出露于华北陆块东北缘的张三沟岩组为一套变质火山-沉积岩系,前人根据变质程度和地层对比将其划归古元古代。本文通过SHRIMP锆石U-Pb年代学研究,获得2517±9Ma、2518±7Ma和2534±26Ma原岩年龄,2439±24Ma、2464±73Ma和2433±71Ma变质年龄。这表明该套变质岩层形成于新太古代晚期,变质时代在新太古代末—古元古代初。结合区域资料,其变质年龄可能代表了古龙岗陆块与位于其北东侧的其它陆块(如佳木斯陆块)碰撞造山的时代,表明华北克拉通在新太古代末—古元古代初期经历过一次重要的克拉通化。Complex of the Zhangsangou Formation is located in the northeastern margin of North China Block, which has been previously considered to be the Paleoproterozoic metamorphic volcanic-sedimentary sequences, mainly according to its metamorphic grade and regional stratigraphic correlation. Based on our filed survey and SHRIMP dating, three samples from Complex of the Zhangsangou Formation have yielded protolith age of 2517±9 Ma, 2518±7 Ma, 2534±26Ma and metamorphic age of 2439±24Ma.2464±73M and 2433 ± 71Ma, respectively, indicating that it formed by metamorphinism at late Neoarchean and reworked at late Neoarchean-early Paleoproterozoic. In combination with regional geological data, its metamorphic time is likely related to a collisional tectonism between ancient Longgang continental bolck and other continental bolcks,which indicates that the North China Block developed a cratonization in late Neoarchean-early Paleoproterozoic.

关 键 词：SHRIMP年代学 张三沟岩组 华北陆块东北缘 吉林 

分 类 号：P597.3[天文地球—地球化学]