Sediment provenance of pre- and post-collisional Cretaceous–Paleogene strata from the frontal Himalaya of northwest India

•Cretaceous–Eocene deposits of frontal Himalaya bring insight into India-Asia collision.•Detrital zircon U-Pb-Hf provenance analyses tests contrasting collisional models.•Tethyan Himalaya sourced sediment to 44–50 Ma deposits of frontal Himalaya.•Zircon from Asia and Kohistan–Ladakh discovered in 44–50 Ma frontal Himalayan rocks.•New data directly challenge Greater India Basin hypothesis. Whereas the timing for India–Asia collision remains debated, contrasting collisional models provide testable predictions in terms of sediment source contributions during the accumulation of Paleocene to middle Eocene deposits now exposed in the frontal Himalayan system. Within the Lesser Himalaya and frontal thrust system of northwest India, discontinuous exposures of the Cretaceous Singtali Formation and upper Paleocene–middle Eocene Subathu Formation yield a record of these early collisional stages. To test competing collisional models, we analyze the provenance of these deposits with new detrital zircon U-Pb and Hf isotopic data which can distinguish among Indian plate, Asian plate, Kohistan-Ladahk arc, and various Himalayan sources. Detrital zircon age distributions for the Singtali Formation are dominated by Paleoproterozoic zircons with a distinct Cretaceous age component, whereas age data from the Subathu Formation record (1) a marked increase in the relative abundance of Cambrian–Neoproterozoic grains, (2) a decrease in the proportion of Paleoproterozoic grains, and (3) distinct Permian and Late Cretaceous–Paleocene age components. All Cretaceous grains from the Singtali Formation yielded crustal Hf isotopic signatures, indicating a distinctive pre-collisional source of Cretaceous grains of Indian affinity. Zircon Hf isotopic signatures from