Linkage between the second uplifting of the Qinghai-Xizang (Tibetan) Plateau and the initiation of the Asian monsoon system

During the period from 25 to 17 Ma BP, when the second plateau uplifting, i.e. the second phase of the Himalays movement, occurred, the Qinghai-Xizang Plateau reached an altitude high enough to change the situation of the general circulation. Such an effect of the plateau on the atmospheric circulation was accompanied by the warning of the tropical ocean, the enhancement of the cross equatorial curren, the enlargement of the marginal sea basins in the east-southeastern Asia, the westward extending of the Asian continent and the regression of the Paratethys Sea. As a result, the thermal difference was enlarged, and the air currents were enhanced between continents and Oceans; finally the Asian monsoon system, mainly the summer monsoon, was initiated. The former planet wind system was then substituted by the monsoon system, and this caused the important environment changes, such as the large shrinkage of the dry steppe in Central Asia, and the extension of the humid forest zone in East Asia. Those changes have been dated at 21.8 Ma BP on the Lingxia profile in the northeastern border of the Tibet Plateau, when the savanna was transformed into the forest.