These mechanisms are crucial for the understanding of Mesozoic and Cenozoic tectonic evolution, paleoclimate and paleontology, such as the interaction between the Himalayas orogenic growth and the Asian monsoon system,[1][2] as well as the dispersal and speciation of fauna.

[8] The first stage involves the collision with an intraoceanic island arc in the Tethys Ocean at approximately 55 million years (Ma) ago.

However, recent studies suggest that volcanic rocks in the Zedong terrane have been altered such that the mobile ion ratios (e.g. K and Na) are unreliable.

[9] The second stage of collision occurred after the oceanic crust of the Great India Basin had been consumed, where the major Indian craton finally came into contact and collided with the Asian continental margin (including the previously "merged" microcontinent, which was interpreted to be the modern Tibetan Plateau) at 25–20 Ma.

[16] The Greater India Basin model is therefore put forward to explain such observation, where the total amount of convergent has actually been dispersed into two separate stages of crustal thickening, i.e. the uplift of the microcontinent (Tibetan Plateau) and the Himalaya orogeny.

The subduction and disappearance of the Great Indian Basin oceanic crust beneath the microcontinent reduces the measurable amount of total convergence expressed by crustal shortening at the surface.

Geological evidence of rocks younger than 59 Ma and deposited on top of the turbidite sequence can be considered as indicators to reconstruct tectonic evolution after collision had begun.

Diversified scientific evidences have been put forward to support such hypothesis, such as paleomagnetic reconstruction,[29] sedimentology and igneous petrology,[30][31] structural geology[32] and geochemistry.

[33] For example, Ingalls et al. (2018) uses δ18O (oxygen-isotope) in meteoric water and Δ47 (clumped-isotope) in non-marine carbonates to reconstruct paleotemperature and paleoprecipitation of the Tibetan Plateau.

This shows that southern Tibet has to be already at its present-day sub-equatorial latitude, such that 10 °C, an extremely warm temperature for highly elevated regions, can be maintained.

[26] The Miocene model suggested that the Indian-Asian collision is the major cause for Tibet's uplift,[28] which is likely to be wrong due to reasons discussed above.

In this model, the Lhasa tectonic block, equivalent to the southern Tibet, experienced initial uplift due to compressional force created when the Indian and Asian continent collided and the Tethys oceanic slab broke off (45—30 Ma).

[28] This interpretation is supported by the thermochronological data of apatite fission tracks from the North Tibetan Plateau, which indicate phases of rapid exhumation and compression from 20 Ma onwards.

[35][36] The Mesozoic model suggested that southern Tibet experienced intense crustal shortening and thickening as early as in Jurassic to Cretaceous time.

[29][30][31][33] The compressional force resulted from the Indian-Asian collision further topped up Lhasa block's elevation and triggered crustal thickening in the North Tibet as the Indian continent proceed northwards.

Royden et al. (2008)[41] suggested a tectonic reconstruction model to illustrate how continental blocks of North and South Tibet has evolved throughout the Indian-Asian collision.

For example, although the above-mentioned Mesozoic uplift model is consistent with the onset timing of South Tibet crustal shortening, other details need to be refined.

[42] In the case of tectonic driven uplift, an active thrust front is present, constantly driving crustal materials upwards.

Since the nearer a spot is to the active thrust front, the greater the effect of weight the uplifted crust has on the land surface, asymmetric subsidence is resulted.

During active uplift and subsidence, accommodation space is created quickly and continually, while erosion rate remains relatively slow.

Therefore, transverse rivers developed on the uplifted mountain range are not able to extend beyond the area nearest to the thrust front, where subsidence is the most intense.

The fact that materials are constantly eroded and removed reduces weight adding on the Earth's crust, causing it to "bounce" higher.

[42] Brookfield (1998)[43] reconstructed the evolution of major river systems of the Indian-Asian collision zone based on tectonic history of the area.

Major focuses are how river systems of the area responded to changing geological processes through time, as well as how regional drainage patterns are capable of reflecting tectonic evolution.

Amidst the collision (which is referred as 20 Ma in Brookfield's model), the shape of river channels were affected by the approaching Indian continent.

Although major river systems still flowed parallel to the thrust, they bent around both sides of the Indian continent since the collision exerted compressional force to the drainage basin.

On the contrary, airmass above the Himalayas and Tibet experiences adiabatic cooling and sinks rapidly, forming an intense high pressure cell.

On one hand, it is believed that the uplift of the Himalayas and Tibetan Plateau is the major trigger of South Asian monsoon onset, since only such elevated landmass can change regional airflow configurations.

However, the only quantitative model which has assigned a significant role for climate suggests the opposite, i.e. the exhumation of the southern flank of the Tibetan plateau is a result of monsoon-intensified denudation.

[51] Although the discussion of this model is limited to 20 Ma onwards, such concept can be implemented to future studies focusing on the Tertiary period so as to better understand how Tibet and the South Asian monsoon co-evolved.