Sedimentary Characteristics And Tectonic Significance Of Suoduo Basin In The Western Section Of Yarlung Zangbo River

The main stratum of the Sodo Basin is the Liuqu conglomerate,which was formed in the same geological event with the Liuxiang Basin in the western segment of the Indian River-Yarlung Zangbo River suture zone.Sodo basin in addition to a small amount of research in geological mapping,almost no related papers published.The study of Sodo basin helps us to understand the collision process more clearly.Although a large number of studies have been carried out in Liuxiang Basin,the formation time is still controversial,and these existing experimental results need to be reorganized.In terms of limiting the uplift process in southern Tibet,Gangdise conglomerate has the same or even more important role as Liuqu conglomerate.Scholars often regard Liuqu conglomerate as the product of contemporaneous or similar age with Gangdise conglomerate.This paper mainly studies the Sodo basin from three aspects : sedimentary characteristics,provenance and tectonic significance.In addition,it also compares with Liuxiang basin and Early Miocene basin.Detrital zircon U-Pb dating,zircon trace element analysis,zircon morphology analysis,gravel statistics,sandstone clastic statistics and paleocurrent methods are used in provenance analysis.In comparison with other basins,sedimentology and provenance were compared.The sediments of the Sodo Basin are mainly from the Zhongba micro-terrane,but the Tethys Himalaya,the Indian River-Yarlung Zangbo suture zone,the Lhasa Terrane and even the West Qiangtang also provide sediments.Only the U-Pb age of detrital zircons from coarse sandstones collected at the bottom of the profile and the morphological analysis of the relative probability curve can be drawn.Although the sediments at the bottom are mainly from Zhongba microterrane,there are other sources of sediments.The sedimentary environment of Sodo basin is debris flow,alluvial fan and braided river,which is almost the same as Liuxiang basin.Both of them are mainly composed of purple glutenite,which are deposited after collision and contacted with the sedimentary unconformity of the Indian River-Yarlung Zangbo River suture zone.They are both bidirectional provenance,and there are many other similarities.Therefore,it should be correct for the predecessors to classify these two basins as Liuqu Group.By sorting out and analyzing previous studies on Liuxiang Basin,the formation time of Liuqu conglomerate was finally determined to be Late Eocene.The formation of Sodo basin is caused by differential uplift during collision.