The formation of the Himalayas and surrounding mountain ranges is one of the most significant tectonic events of the Cenozoic, with far reaching impacts on both regional and global climate. The Pamir represents the indented westward continuation of the northern margin of the Tibetan Plateau making them a key study area to examine internal deformation and intracontinental subduction processes. Yet the tectonics of the Pamir Salient is poorly understood. Much debate is ongoing, regarding the extent of indentation and mechanisms driving uplift of the Pamir. This project seeks to provide constraints on the timing of Pamir evolution and examine the impact of Pamir formation on the regional climate using a variety of techniques to date and interpret observed variations in terms of provenance, tectonism and climate, the results of which are presented here.
At ~41 Ma the Tarim Sea retreated from the Aertashi region. Continental deposition ensued, dominated by the western Kunlun to the south.
By 24-22 Ma, basinward expansion of the NW margin of Tibet coincides with the initiation of Pamir indentation. Activation of strike slip faulting, growth strata and exhumation along the Kashgar-Yecheng Transfer System is evidenced in the Aertashi region which may be linked to a pull-apart basin.
By ~18.5 Ma, the onset of northward thrusting of the Kunlun hinterland and southward migrating foreland of the Tian Shan positions the Aertashi region in the depocenter of the Tarim Basin.
By ~15 Ma, the Pamir Salient had propagated sufficiently far north, that the north Pamir, and by 11 Ma the Central Pamir were proximal to Aertashi.
The Eocene – mid Miocene climate in the Tarim Basin was highly seasonal with evidence of increased aridity. Aridification was interrupted by a short period of increased humidity at ~17.6-15 Ma which can be linked to the mid-Miocene climate optimum, or a facies change. Limited comparative studies make climatic conclusions tentative.