Zircon U-Pb Ages and their Implications of the Jiadanqiao Formation of the Ebian Group Metamorphic Clastic Sedimentary Rock in the Jinkouhe area of the Western Sichuan Province
The Ebian Group in the Jinkouhe area of the western Sichuan Province provides a good opportunity to understand the Precambrian tectonic evolution of the western Yangtze Block.The LA-ICP-MS U-Pb chronology of detrital zircons from the lower grade metasedimentary rocks of the Jiadanqiao Formation in Ebian Group is studied.The results show that the U-Pb age of JKH10 zircon ranges from 2750 to 891 Ma,and the youngest detrital zircon is 891±9 Ma,indicating that the maximum sedimentary age of this group is～890 Ma.The dating results of the samples in this paper have the characteristics of multi-peak age spectra,mainly concentrated in 4 ages:1888～1724 Ma,1676～1509 Ma,1439～1231 Ma and 1057～891 Ma,the peak ages were～1800 Ma,～1600 Ma,～1250 Ma and～980 Ma,respectively.Combined with previous studies,the sedimentary age of the Jiandanqiao Formation of Ebian Group in the study area is about 890～860 Ma,and the clastic sedimentary materials mainly come from the Paleoproterozoic,Mesoproterozoic and early Neoproterozoic magmatic rocks in the western and northern margins of the Yangtze block.Regionally,the Ebian Group should not be compared with the Huili Group,Dengxiangying Group,Kunyang Group and other late Mesoproterozoic strata,and its stratigraphic age is more comparable to the Neoproterozoic Yanbian Group.
western Yangtze BlockNeoproterozoicEbian Groupdetrital zircon U-Pb dating
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