Discovery of a complete ophiolite section in the Jueweng area, Nagqu County, in the central segment of the Bangong Co-Nujiang junction zone, Qinghei-Tibet Plateau

A relatively complete ophiolite section has been found for the first time in the Jueweng area, Nagqu County, in the central segment of the Bangong Co-Nujiang junction zone. From below upward the section consists of metaperidotites, pyroxene peridotite, cumulates, massive gabbro, dike swarms, carbonatite, pillow lavas and radiolarian cherts. It is unconformably overlain by the Late Cretaceous Jingzhushan Formation. Isotopic dating of cumulates yields an age of 128 Ma (by the single-zircon fusion method), thus verifying that the age of the ophiolite is Early Cretaceous. This finding denies the view that no complete ophiolite section in the central segment of the Bangong Co-Nujiang junction zone and demonstrates that there also exists Cretaceous ophiolite in addition to Jurassic ophiolite. This furnishes evidence for the determination of the final closing time of the central segment of the Bangong Co-Nujiang junction zone.