The Upper Cretaceous to Lower Tertiary sediments in the Indus-Yarlung suture zone provide critical records on the history of accretion along the southern margin of Asia prior to, and during, the India-Asia collision. In this article, we report field and petrographic observations, in situ detrital zircon U-Pb ages, Lu-Hf isotopic analyses, and Cr-spinel electron microprobe data from the Upper Cretaceous to Lower Tertiary sedimentary rocks of the Renbu mélange zone in east Xigaze, southern Tibet. The Renbu mélange zone consists of two serpentinite mélange subzones separated by a mud-matrix mélange. Using similarities found in the compositions of detrital Cr-spinels and detrital zircon U-Pb ages, we propose to correlate the northern Renbu mélange subzone with the upper part of the Xigaze forearc basin. Detrital zircons from sandstones in the southern Renbu mélange subzone indicate an influx of Cretaceous–early Cenozoic zircon grains with juvenile Hf isotopic compositions, suggesting a provenance from the Lhasa terrane, especially the Gangdese arc. Compared to the mélange in the western Xigaze, our new results show that much younger sediments were deposited on the top of the accretionary wedge, with the youngest U-Pb age cluster including six single grains in the range of 64–53 Ma and a large peak at 67 Ma. Our results support the idea that the foreland basin developed along the Indus-Yarlung suture during the India-Asia collision.

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