Formation of mountains of the Central Tien Shan is usually explained by the isostatic response of the crust to its shortening caused by the India-Eurasia collision. The rise of the region in the period from Oligocene to Late Pliocene (2 myr ago) reached ∼700 m on average, which corresponds to the isostatic response. For the last 2 myr (Late Pliocene–Quaternary), the rate of rise increased by an order of magnitude. This is proved by the coarsening of Cenozoic molasse up the sections, acceleration of cutting of drainage systems into ridges, and formation of new ridges within basins. In the Quaternary, most of intermontane basins underwent uplifting, though not so intense. The average rate of lateral crustal shortening increased ∼2–2.5 times only, and the contribution of this process to the Late Pliocene-Quaternary orogeny was no more than 10%. The acceleration of rise was caused mainly by the convective replacement of the mantle lithosphere by the less dense asthenosphere. This was due to the quick softening of the mantle lithosphere as a result of the infiltration of active fluid from the lower mantle. Such accelerations of crustal uplifting took place in the Pliocene and Quaternary in many continental regions. This evidences that mantle processes, first of all, the full or partial replacement of the mantle lithosphere by the asthenosphere, played an important role in the formation of mountains.
The Ming-Kush-Kökömeren Zone in the Middle Tien Shan is a transpressional structural unit, i.e., a longitudinal recent faultline depression, where manifestations of transverse shortening (intense folding, reverse and thrust faulting) are combined with left-lateral offset along the same faults; the left-lateral offset is commensurable to vertical separation along reverse and thrust faults or it even exceeds the latter. The complicated deformation within this zone has developed most intensely since the late Pliocene and reached a peak in the Pleistocene. However, the origin of this structural unit was at the onset of neotectonic stage, as evidenced from the Oligocene-lower Miocene conglomerate unit, which was formed as a product of the destruction of reactivated Hercynian thrust faults and nappes in the southern wall of the zone. The conglomerate filled a narrow ramp valley that formed in front of thrusts, probably due to the strike-slip offsets along boundary faults. Similar transpressional linear zones-Tessyk-Sary-Bulak, Uzunbulak-Oy-Kain, Kara-Köl, and Chong-Kemin (Kemin-Chilik)-are known in the Middle Tien Shan.