Zircon U-Pb geochronology of tuffite beds in the Baishugou Formation:Constraints on the revision of Ectasian System at the southern margin of the North China Craton  

作　　者：Xiyan ZHU Shiyan WANG Wenbo SU Taiping ZHAO Lanyin PANG Mingguo ZHAI 

机构地区：[1]Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China [3]Henan Institute of Geological Survey,Zhengzhou 450001,China [4]School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083,China [5]Key Laboratory of Mineralogy and Metallogeny,Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,Guangzhou 510640,China [6]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Earth Sciences》2020年第11期1817-1830,共14页中国科学（地球科学英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.41630211,41872198,41772028&41890834)。

摘　　要：The Xiamaling Formation of 1.4–1.35 Ga in Jixian Section and adjoining areas represents a unique Ectasian Period(Mesoproterozoic)sedimentary sequence in the North China Craton(NCC).Studies carried out during the last decade have contributed significantly in improving our understanding about the Ectasian sedimentation tectonics in the NCC during this transitional interval between the breakup of Supercontinent Columbia and the assembly of Rodinia.The present study reports,for the first time,tuffite beds interlayered with carbonaceous-siliceous slate-phyllite in the upper Baishugou Formation(western Henan Province),at the southern margin of NCC.The LA-MC-ICPMS U-Pb geochronology of zircons from two tuffite samples has yielded almost identical ages of 1330±10 Ma(MSWD=0.43,N=38)and 1332±10 Ma(MSWD=0.90,N=24),that constrain a 1.33 Ga depositional age(Ectasian Period)for the Baishugou Formation.A close similarity in lithological characteristics and their respective superimposed lithostratigraphic relationships of the Baishugou and Xiamaling formations,underline a comparable depositional environment for them.The high-precision geochronology data on the Baishugou Formation would stimulate a relook into the Meso-Neoproterozoic chronostratigraphic framework of the NCC,and further research would lead to a comprehensive understanding of the geological evolution of the NCC during Ectasian Period and its correlation with analogous global events.

关 键 词：Tuffite Baishugou Formation Zircon U-Pb ages Ectasian Period North China Craton(NCC) 

分 类 号：P597.3[天文地球—地球化学] P542[天文地球—地质学]