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The Neo-Tethys Ocean was an eastward-gaping triangular oceanic embayment between Laurasia to the north and Gondwana to the south. The Neo-Tethys Ocean was initiated from the Early Permian with mircoblocks rifted from the northern margin of Gondwana. As the microblocks drifted northwards, the Neo-Tethys Ocean was expanded. Most of these microblocks collided with the Eurasia continent in the Late Triassic, leading to the final closure of the Paleo-Tethys Ocean, followed by oceanic subduction of the Neo-Tethys oceanic slab beneath the newly formed southern margin of the Eurasia continent. As the splitting of Gondwana continues, African-Arabian, Indian and Australian continents were separated from Gondwana and moved northwards at different rates. Collision of these blocks with the Eurasia continent occurred at different time during the Cenozoic, resulting in the closure of the Neo-Tethys Ocean and building of the most significant Alps-Zagros-Himalaya orogenic belt on Earth. The tectonic evolution of the Neo-Tethys Ocean shows different characteristics from west to east: Multi-oceanic basins expansion, bidirectional subduction and microblocks collision dominate in the Mediterranean region; northward oceanic subduction and diachronous continental collision along the Zagros suture occur in the Middle East; the Tibet and Southeast Asia are characterized by multi-block riftings from Gondwana and multi-stage collisions with the Eurasia continent. The negative buoyancy of subducting oceanic slabs can be considered as the main engine for northward drifting of Gondwana-derived blocks and subduction of the Neo-Tethys Ocean. Meanwhile, mantle convection and counterclockwise rotation of Gondwana-derived blocks and the Gondwana continent around an Euler pole in West Africa in non-free boundary conditions also controlled the evolution of the Neo-Tethys Ocean. [ABSTRACT FROM AUTHOR]

Numerous continents have rifted and drifted away from Gondwana to repeatedly open ocean basins over the past ∼500 million years. These Gondwana-derived continents drifted towards and collided with components of the Eurasian continent to successively close the preexisting oceans between the two. Plate tectonics satisfactorily describes the continental drift from Gondwana to Eurasia but does not define the geodynamic mechanism of continuously rifting to collisions of continents in the Tethyan Realm. After reappraisal of geological records of the rift, collision and subduction initiation from the surface and various geophysical observations from depth, we propose that Eurasia-directed subducting oceanic slabs would have driven Tethyan system in the Phanerozoic. The Eurasia-directed subduction would have dragged the passive Gondwana margin to rift and drift northwards, giving birth to new oceans since the Paleozoic. The closure of preexisting oceans between the Gondwana-derived continents and Eurasia led to continental collisions, which would have induced the initiation of oceanic subduction in the Tethyan Realm. Multiple episodic switches between collision-subduction-rift repeatedly led to the separation of continental fragments from Gondwana and dragged them to drift towards Eurasia. The final disappearance of Neo-Tethys would have induced collision of the Gondwana-derived continents with the Eurasian continent, giving rise to the Cenozoic Alpine-Zagros-Himalayan collisional system. Therefore, the Eurasia-directed oceanic subduction would have acted as a 'one-way train' that successively transferred the ruptured Gondwana continental fragments in the south, into the terminal in the north. In this regard, the engine of this "Tethyan one-way train" is the negative buoyancy of subducting oceanic slabs. [ABSTRACT FROM AUTHOR]