Zircon SHRIMP U-Pb ages of the “Xinghuadukou Group” in Hanjiayuanzi and Xinlin areas and the “Zhalantun Group” in Inner Mongolia,Da Hinggan Mountains  

作　　者：MIAO LaiCheng LIU DunYi ZHANG FuQin FAN WeiMing SHI YuRuo XIE HangQiang 

机构地区：[1]Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China [2]Beijing SHRIMP Center, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China

出　　处：《Chinese Science Bulletin》2007年第8期1112-1124,共13页

基　　金：Supported by the National Natural Science Foundation of China(Grant Nos.40473030 and 40234045);the Chinese Academy of Sciences(Grant No.KZCX2-104)and the Key Laboratory Mineral Resources,Chinese Academy of Sciences

摘　　要：A report is presented of SHRIMP zircon U-Pb dating data of meta-igneous and meta-sedimentary rocks of the Xinghuadukou Group(Xinlin-Hanjiayuanzi area,Heilongjiang Province)and meta-volcanic rocks of the Zhalantun Group(Zhalantun district,Inner Mongolia).The SHRIMP analyses show that the meta-igneous rocks from the Xinghuadukou Group formed at 506±10―547±46 Ma,belonging to Early-Middle Precambrian,whereas the meta-sedimentary rocks yielded detrital zircons,with ages of 1.0―1.2,1.6―1.8 and 2.5―2.6 Ga,indicative of deposition age at least<1.0 Ga. Meta-basic volcanic rocks from the Zhalantun Group have a formation age of 506±3 Ma.These data suggest that both the Xinghuadukou and Zhalantun Groups formed during Cambrian and/or Neoproterozoic time,rather than Paleoproterozoic time as previously thought.Early Precambrian inherited zircons in the meta-igneous rocks and numerous Precambrian detrital zircons in the meta-sedimentary rocks imply that these rocks were formed proximal to older crust.It is inferred that the Xinghuadukou and Zhalantun Groups represent Cambrian and/or Neoproterozoic vol- cano-sedimentary sequences formed in an active continental margin setting.A report is presented of SHRIMP zircon U-Pb dating data of meta-igneous and meta-sedimentary rocks of the Xinghuadukou Group （Xinlin-Hanjiayuanzi area, Heilongjiang Province） and meta-volcanic rocks of the Zhalantun Group （Zhalantun district, Inner Mongolia）. The SHRIMP analyses show that the meta-igneous rocks from the Xinghuadukou Group formed at 506±10-547±46 Ma, belonging to Early-Middle Precambrian, whereas the meta-sedimentary rocks yielded detrital zircons, with ages of 1.0-1.2, 1.6-1.8 and 2.5-2.6 Ga, indicative of deposition age at least 〈1.0 Ga. Meta-basic volcanic rocks from the Zhalantun Group have a formation age of 506±3 Ma. These data suggest that both the Xinghuadukou and Zhalantun Groups formed during Cambrian and/or Neoproterozoic time, rather than Paleoproterozoic time as previously thought. Early Precambrian inherited zircons in the meta-igneous rocks and numerous Precambrian detrital zircons in the meta-sedimentary rocks imply that these rocks were formed proximal to older crust. It is inferred that the Xinghuadukou and Zhalantun Groups represent Cambrian and/or Neoproterozoic volcano-sedimentary sequences formed in an active continental margin setting.

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分 类 号：P535.2[天文地球—古生物学与地层学]