AN INTRACONTINENTAL RIFTING TO OROGENY: THE SONGPAN–GARZÊ TERRANE, NORTHEASTERN TIBETAN PLATEAU, CHINA
Here we focus on Permian evolution and combine with the sedimentology, geochemistry and geochronology to decipher the mystery of SGT. We have discovered Middle-Late Permian conglomerate, sandstone and mudstone in SGT, which displayed fining-upward sedimentary sequences and indicated deepening water environment. Detrital zircons from Lower Permian show a distinct age cluster with 720-850 Ma which indicate simple source from Yangtze Block. Considering the OIB-type Late Permian basalt (263-256 Ma) in SGT same as Emeishan flood basalt (265-258 Ma), we advocated that Songpan-Garzê Terrane originated from an intracontinental rifting within Yangtze Block during Middle-Late Permian, and developed to comparative deep water until Late Triassic (Carnian-Noria). Subsequent orogeny and deformation of SGT initiated coevally with or little earlier than latest Triassic (Noria-Rhaetian) Sichuan foreland basin based on the detrital zircon provenance. This crustal structure and evolution are comparable with Pyrenean orogeny in west European continent.