A 4000‐km‐Long Late Devonian Continental Arc in Eastern Asia and the Opening of the Palaeo‐Tethys

Abstract

ABSTRACTThe Palaeozoic–early Mesozoic Palaeo‐Tethyan evolution was crucial for the formation of present‐day eastern Asia. However, the exact timing and mechanism of the opening of the main Palaeo‐Tethys Ocean, represented by the Longmuco‐Shuanghu‐Changning‐Menglian‐Bentong‐Raub Suture, remain debated. Here, we report U–Pb–Hf isotopes and trace elements for Late Devonian detrital zircons from the Batang area, which exhibit arc‐like geochemical signatures, indicating strong continental arc magmatism in the North Qiangtang terrane. These characteristics match well with those of coeval zircons from the Indochina and Hainan terranes, thus defining a 4000‐km‐long Late Devonian continental arc. Supported by available geological and geophysical evidence, our results suggest that the southward subduction of the Jinshajiang‐Ailaoshan‐Song Ma Ocean led to the northward migration of the North Qiangtang‐Indochina‐Hainan continental ribbon and the subsequent opening of a back‐arc basin, which evolved into the main Palaeo‐Tethys Ocean.