Shear convergence of plates and suturing of terranes: a new model for the comsumption of the Meso-Tethys

The Meso-Tethys was a sea lying between Laurasia and Gondwana during the Middle and Late Mesozoic. Following the termination of the sea during the Late Cretaceous, the Bangong-Nujiang suture zone with a length of more than 1000 km was left over. The argument about the extinction of the sea still remains current. Many researchers have insisted on the eastern Pacific model for a long time, i.e.they owed its extinction to the subduction of the oceanic crust. However, the authors have put forward in this paper a new model for the consumption of the Meso-Tethys due to the shear convergence of plates and suturing of terranes, and argued that the Meso-Tethys is an unusual sea in which the narrow basins are isolated and vary in ages. It can be deduced that no large-scale subduction of the oceanic crust occurred at that time. The consumption of the Meso-Tethys commenced during the late Early Jurassic, when the eastern part of the Gangdise-Nyainqentanglha plate began to be sutured together with the Qiangtang-Nujiang-Lancangjiang-Jinshajiang plate without subduction, while the middle and western parts of the Meso-Tethys were still open. Till the Middle and Late Jurassic, the rifting apart from the southern terranes and northward suturing of the tectonic terranes on the northern side of the middle and western parts of the Meso-Tethys onto the Qiangtang-Nujiang-Lancangjiang-Jinshajiang plate took place almost simultaneously. The entire processes came to an end, and the two plates cited above were gradually sutured together during the latest Early Cretaceous. At the same time, the bulk of the middle and western parts of the Meso-Tethys disappeared successively. And during the latest Cretaceous, the large-scale subduction of the Neo-Tethys forced the two plates to be further sutured together, resulting in the continent-continent collision. Finally the Meso-Tethys terminated in response to the intrabasinal convergence including folding and thrusting and collisional orogenesis of the oceanic and intermediate crust.