Interaction Between The Uplift Of The Tibetan Plateau And The Eastern Asian Multispheres Since 1.2 Ma

During past decades, the development of earth science indicates that the environmental conditions of earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. Investigations on the interaction or mechanism between these multiple components of the earth system became a hot issue of geosciences field. The tectonic movement/uplift of the lithosphere, as discussed in many investigations, controlled the global environmental change during the whole Cenozoic period on the 10~5-10~7 years time scale. Given this discussion, the tectonic movement/uplift of lithosphere provides a good opportunity for the research of interaction between the complex earth system components. Specifically, our efforts are paid to the recent 1.2Ma when the environment in China changed dramatically. First, also the dominant change of Chinese environment since 1.2Ma B.P. is the tectonic uplift of the Tibetan Plateau (TP). Hence, this lithosphere change is proved to be the trigger and amplifier of the whole system by previous investigations. However, the advance and detail research are limited.Well situated at the eastern margin of the Tibetan Plateau, the geomorphology evolvement of the Weihe River is a promising evidence to record the tectonic uplift events of the TP. The magnetostragraphy study of loess deposited on the river terrace indicated that there were at least two dramatic down-cutting events in the Longxi Basin during 1.0-0.8Ma. The analysis of river terrace characters and the temporal coincidence of records in other regions confirm our proposal that these two down-cutting events of Weihe River are tectonic driven. Integrated our results with other intensively studied records in and around the Tibetan Plateau from 1.2Ma; we suggest two tectonic uplift stages of TP with the first one during 1.2-0.6Ma and the second one during 0.2-0.15Ma. Moreover, the first stage can be divided into three sub-stages: l)1.2-1.1Ma, characterized by the down-cutting of the Yellow river in Jishi Gorge, 2)0.9-0.8Ma, the main phase of the tectonic uplift, and 3) 0.6Ma.Before attempting a systematic discussion of the interactions between lithosphere, atmosphere, hydrosphere, and biosphere of China, the evolution of every sphere since 1.2Ma are considered. The magnetic fabric-based reconstruction of paleowind direction in the northeastern flank of Qilian Mountains reveals the near surface air circulation changes, which are dictated by the East Asian Monsoon, in ~0.78Ma (from NW-SE to W-E) and 0.5Ma (a NE-SW dominant direction established). Time of the first paleowind direction change is temporal related to the end time of the major tectonic uplift of TP casually, which may suggest the affection of tectonic uplift on the atmospheric circulation. Studies on the loess magnetic fabric and magnetic susceptibility (MS) in semi-arid region, such as northeastern flank of Qilian Mountains,...