Subsidence characteristics of Turpan Basin and its tectonic implications

The Turpan Basin, a back-arc basin formed during Late Permian, underwent first thermal subsidence and then flexure subsidence. The thermal subsidence took place during Late Permian and Early Triassic following the period of magmatic activities in this region. The flexural subsidence was throughout the Middle Triassic to Early Tertiary induced by erogenic movements which produced periods of high subsidence rates. Accelerated subsided periods occurred during Late Triassic/Early Jurassic, Late Jurassic, terminal Jurassic/initial Cretaceous, and terminal Cretaceous/early Cenozoic, indicating the effect of the collision and accretion onto the south Asian continental margin of the Qiangtang Block in Late Triassic/Early Jurassic, the Gangdise Block in Late Jurassic and terminal Jurassic/initial Cretaceous, and the Indian subcontinent in the terminal Cretaceous/early Cenozoic. There are relatively large breaks in the variation of the petrologic and geochemical data among these events. The Turpan Basin evolved from a back-arc basin in late Paleozoic into a foreland basin in Mesozoic, and a large intermontane basin of the Tianshan Mts. in Cenozoic.