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A comprehensive study of the sediment source-to-sink history of basins arranged along the Bangong-Nujiang Suture Zone (BNSZ) is critical for understanding the early Cenozoic topography and drainage systems of central Tibet and its implications for the uplift history of the Tibetan Plateau. Nevertheless, previous provenance analyses work mainly focused on the middle-eastern segment of the BNSZ, those Paleogene basins in the western segment have received less attention, which hinders a full understanding of the early Cenozoic topography of central Tibet. In this study, based on a chronostratigraphic framework developed for the lower Cenozoic continental redbeds of the Gaize Basin, we applied detrital zircon U-Pb geochronology to the well-exposed Paleogene Suonahu Formation in order to reconstruct the basin's source-to-sink history. Integrating these new data with detrital zircon U-Pb results from the underlying Kangtuo Formation, we recognize a major secular shift in sediment provenance characterized by inputs of Lhasa-derived clasts during the Late Eocene. Moreover, we applied statistical analysis to compare the U-Pb age spectra of Eocene strata in the Gaize-Nima-Lunpola basins in order to assess similarities between them and potential source regions. Our study confirms a paleogeographic scenario in which these Paleogene basins most likely were part of a low-elevation intermontane valley. • Analysis of detrital zircon U-Pb geochronology of Paleogene strata in Gaize Basin. • A major shift in provenance occurred between the Kangtuo and Suonahu formations. • Cenozoic clastic strata in the Gaize-Nima-Lunpola basins share a similar provenance. • The Gaize-Nima-Lunpola basins belonged to a Paleogene low-elevation valley. [ABSTRACT FROM AUTHOR]

Determining the provenance of Cenozoic strata in the Qaidam Basin is key to understanding the basin-mountain coupling history in the northern Tibetan Plateau (TP). However, the specific source areas of Cenozoic strata in the northern Qaidam Basin remain highly debated. Here, we combine analyses of detrital zircons U Pb geochronology for recent and ancient fluvial sediments from the northern Qaidam Basin to trace source areas of Cenozoic strata and reconstruct related mountain-building processes. The results indicate that the diagnostic 270–240 Ma zircon U Pb peak, which was previously recognized as the unique input of a southern source area, is widespread in the recent fluvial sediments of the northern Qaidam Basin. Given our new zircon U Pb data, the source-to-sink transport processes of Cenozoic sediments in the northern Qaidam Basin can be summarized as follows. (1) The northern Qaidam Basin has received the eroded detrital material from a dominantly northern source throughout the Cenozoic. (2) The Qaidam BeiShan was uplifted already at least by the early Eocene and served as the single contributor of detritus to the Dahonggou (DHG) region, suggesting that far-field stress due to the India-Asia collision had been propagated to this region as early as the early Eocene. (3) An abrupt change in provenance is observed in the DHG region during 46.5–43.7 Ma. We interpret this middle Eocene source change as reflecting the onset of growth of the North Altyn Tagh Range, implying that the North Altyn Tagh Range was already serving as an important source area for the DHG region by the middle Eocene. (4) The South Qilian Range served again as the dominant source area for the DHG region after 24.6 Ma. The shift in provenance from the North Altyn Tagh Range to the South Qilian Range can be attributed to the uplift of the Saishiteng Shan. • Cenozoic detritus in northern Qaidam Basin exclusively from northward source • 270–240 Ma zircon U Pb peak widely seen in recent fluvial sediments in north basin • The Qaidam BeiShan had uplifted already at least in the early Eocene. • North Altyn Tagh and South Qilian ranges provide dominant sources. • Multiple source-to-sink stages of northern Qaidam Basin from ~>50.4 to 10.8 Ma [ABSTRACT FROM AUTHOR]