Jurassic and Cretaceous Sedimentary Record during the Basinorogeny Transition in the Nyalam area, Southern Tibet, China

Key words: 
• sedimentary record /
• basinorogeny transition /
• JurassicCretaceous /
• southern Tibet

Abstract: The evolutionary history from the Jurassic passive continental margin to the Cretaceous foreland basin of the northern Indian plate where are located in the northern Himalayas of the southern Tibet. The huge transgressregressive cycle has been developed during the Jurassic. The Himalayan Tethysan oceanfloor spreading velocity is obviously sped up at late Jurassic, from about 0.32㎝/a of the early and middle Jurassic up to 1.24㎝/a of the late Jurassic. The Cretaceous Himalayan foreland basin evolution is divided into the two stages that included the early deepwater flysch basin and the late marine molasse basin in the southern Tibet. The upward rapid deepening sandmuddy flysch formation and black shale formation and islandarc volcanic rocks are developed in the early foreland (early Cretaceous), the upward shallowing and coarsening marine molasse formation in the late foreland (late CretaceousEocene). The Himalayan Tethysan in the southern Tibet was finally closed at about 4038Ma of the midlate Eocene.