Chronological Study and Enlightment of detrital zircon of Carboniferous——Permian strata in the eastern part of the Lhasa
The Carboniferous-Permian marine strata are continuously exposed in the eastern part of the Lhasa massif,and the study of their provenance is of great significance for revealing the evolution process of the Sumdo Paleo-Te-thys Ocean.In this paper,the detrital zircon chronology of the Carboniferous-Permian strata in the Niangpu area of Gongbogyamda and Longde area of Nyingchi was carried out,and the dating results showed that the youngest age cluster of the strata is between 314 Ma and 322 Ma,indicating that their sedimentary age was not earlier than the Late Carboniferous.Comprehensively comparing the previously reported age spectrum of detrital zircon in the Car-boniferous-Permian strata of Canning and Perth Basins in Australia,the magmatism record of the Sumdo Paleo-Te-thys Ocean evolution in the Lhasa massif,and the age spectrum of the accreting complex clastic zircon in this set,this paper believes that the Carboniferous-aged detrital zircon in this set of strata is mainly derived from magmatism during the evolution of the Sumdo Paleo-Tethys Ocean.The Sumdo Group(AnOs)in Gongbogyamda and the Sumdo Formation(C2P1s)in Zhikong-Sumdo area are the same strata,and they are part of the Songduogu Tethys Ocean accretionary complex.The strata of the Nuocuo Formation(C1n)in the Longde area of Nyingchi are similar to those of the Laigu Formation(C2P1l)in Dangxiong,which is a stable deposition on the edge of the Sumdo Paleo-Tethys Ocean.
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