Cenozoic intracontinental tectonics of Mongolia and its climate effects: A synthesized review

Mongolia, a major world-class site of Cenozoic intracontinental tectonics, provides a key proxy for the long-term dynamics of Eurasia, but there has been considerable debate about the principal driving forces responsible for the intracontinental deformation. Here, we show that the Cenozoic tectonic development of Mongolia and surrounding regions was largely a consequence of the interaction of four factors: the India-Asia collision, extension of the Baikal Rift, lithosphere and mantle processes beneath the Khangay Dome, and Pacific subduction. The recent tectonic development of the Mongolian and Gobi Altay, the Gobi Tianshan Mountains, and western South Mongolia were controlled by the interplay of sinistral and dextral strike-slip faults that have formed since ∼5–8 Ma by intraplate transpression. The Khangay Mountains formed on a deep seated warm upwelling that was derived from >80 km depth in the upper mantle. Khangay consists of many Cenozoic basalts, the origin and evolution of which are linked to thinning of the lithosphere via upwelling of a mantle plume. The Khentey Mountains were slightly rejuvenated to form an arched uplift caused by final Cenozoic transpressional forces from the India-Asia collision, which overlap with the effects of Pacific subduction. The Cenozoic geology of East Mongolia has a weak inheritance from Mesozoic events related to the Pacific subduction. The Sayan-Khuvsgul mountainous region formed by NS-compression against stable Siberia at ca. 10 Ma. We propose that the latitudinal ranges of Tannu-Ola in Tuva, the Tsagaan Shuvuut and Khan Khukhey Ranges and the Uvs Basin in Mongolia are included in the South Sayan tectonic block, as they all formed as a result of intraplate movements derived from the India-Asia collision. The bulwark of the Tibetan plateau displaced atmospheric Hadley Cells northward and has acted as an orographic climate barrier against the Indian monsoon that led to aridification, lack of drainage, and to local internal erosion during the Cenozoic in Mongolia.