DISCOVERY AND SIGNIFICANCE OF CRETACEOUS FOSSILS FROM THE XIGAZE FORE-ARC BASIN, TIBET

The Xigaze Cretaceous forearc basin located between the Lhasa Block an d Indus-Yarlung Suture was filled with flysch deposits during the mid- Cretaceous, as the Tethys oceanic crust was being subducted underneath Eurasia. The flysch comprises the Xigaze Group, dominated by the Angr en Formation. Well preserved, newly discovered foraminifera within the Angren Formation constrain its age to late Albian to late Coniacian. Radiometric dating of the ophiolite belt impinging on the southern edg e of the forearc basin yielded an age of 120 + 10 Ma, which implies th at the deposition in the forearc basin occurred shortly after initiati on of the subduction of the Neotethys. (C) 1998 Elsevier Science Ltd. All rights reserved.