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The uplift of the Tibetan Plateau has been widely associated with India-Asia continental collision during the Cenozoic. However, recent studies have proposed that a proto-Tibetan Plateau in central Tibet was elevated during the late Mesozoic. This paper improves that understanding by focusing on the Cretaceous terrestrial strata in the Gerze area of central Tibet. Our studies suggest that the Qushenla Formation in the Nare area contains alluvial fan conglomerate intercalated with rhyolitic ignimbrite and vesicular rhyolite. Zircon U Pb dating of rhyolitic ignimbrite (103.9 ± 1.4 Ma) and two granitoid boulders of conglomerate (106.0 ± 1.6 and 106.1 ± 1.5) indicate that the Qushenla Formation was deposited during the late Albian. The compositions of the Qushenla Formation conglomerate were dominated by hypabyssal intrusions on the southern Qiangtang terrane, which recorded a rapid uplift and denudation process in the late Albian, accompanied by intense volcanic eruptions. The second set of terrestrial strata is the Upper Cretaceous Jingzhushan Formation alluvial fan-braided river deposits, which can be divided into a lower conglomerate member (Member 1) and a upper sandstone member (Member 2). The large amount of bioclastic limestone fragments in the Member 1 show that they come from the Upper Cretaceous Langshan Formation in the central and northern Lhasa subterranes. While in the Member 2, abundant limestone debris, detrital zircon yielding Jurassic–Cretaceous ages with ε Hf (t) values between −18.6 and + 8.4, and occurrence of volcanic and ancient zircon grains indicate a volcanic-sedimentary source located in the central and northern Lhasa subterranes, with some input from the Bangong-Nujiang suture zone. This suggests that the central and northern Lhasa subterranes experienced rapid crustal uplift in the Late Cretaceous, thus ending the marine sedimentary environment since the Jurassic. Based on the temporal and spatial sedimentary characteristics of the Qushenla and Jingzhushan formations as well as the regional data, our integrated study suggests that the central plateau (Lhasa and southern Qiangtang terranes) experienced a complex uplift history during the Aptian-Turonian, with southwards stepwise growth in time and space. Furthermore, the uplift mechanism of the central plateau is complex, which was controlled by the diachronous closure of the Bangong-Nujiang Tethyan Ocean from east to west during the Early Cretaceous, and by the far-field forces associated with northwards subduction of the Neo-Tethys Ocean during the Late Cretaceous. [Display omitted] • There are two sets of Cretaceous terrestrial strata in the Gerze area. • Gerze area had a residual sea retreat southwards during Aptian-Turonian. • Central Tibet experienced a dual diachronic uplift of E–W and N S in Aptian-Cenomanian • We suggest that the early uplift process of central Tibet was phased. [ABSTRACT FROM AUTHOR]

Reconstructing the evolution of the Sumdo Paleo-Tethyan Ocean (SPTO) is important for understanding the transition from the Paleo-Tethyan system to the Neo-Tethyan system. The existence of the SPTO is inferred from the presence of an (ultra-)high pressure metamorphic belt and dismembered ophiolite bodies that separate the southern Lhasa and northern Lhasa terrane. This paper presents new geochronological and geochemical data for the Luobadui Formation in the Lhasa terrane. The geochemical difference between the Lower Luobadui volcanics and the Upper Luobadui volcanics suggests a source transition from a depleted mantle source to an enriched mantle source, which indicates continental-arc subduction. The integrated geological evidence suggests that the SPTO initially opened during the late Carboniferous (ca. 304 Ma), as verified by the earliest record of oceanic crust. Our new data for the Luobadui volcanic rocks, together with the metamorphic and sedimentary records, support northward subduction of the SPTO lithosphere beneath North Lhasa, most likely starting during the Early Permian (ca. 275 Ma) and lasting until the Middle Permian (ca. 260 Ma). The main closure of the SPTO occurred during Middle–Late Triassic (ca. 240–220 Ma), as recorded by medium-pressure metamorphism and syn -collisional magmatism. The Wilson cycle of the SPTO is hereby reconstructed, providing significant insights into the amalgamation of the Tibetan Plateau. • The arc volcanic rocks from Luobadui Formation formed mainly during 275–260 Ma. • The Luobadui sedimentary detritus was sourced from the Lhasa terrane. • The Wilson cycle of the Sumdo Paleo-Tethys Ocean was reconstructed. [ABSTRACT FROM AUTHOR]