Abstract:

The formation of the Qinghai-Tibet Plateau as Earth's “third pole” is the most distinguishing and significant result of neotectonic movements under Earth's rhythmic tectonic events since the Cenozoic era. The characteristics and importance of tectonic landforms in the region, the tectonic regime of the plateau, the evolutionary dynamics and the impact and long-range effects of the plateau uplift on peripheral basins and even the entire Chinese subcontinent have been the focus of academic attention to this day. This article redefines the range of tectonic landforms of the Qinghai-Tibet Plateau, and establishes the importance of the plateau uplift to global tectonics. According to the results, the remote effects of the Qinghai-Tibet Plateau and its south/north extension spans across Asian along 105°E longitude, in general, reaching the Arctic Ocean in the north and reaching the Pacific Ocean in the south. Hence, this article uses the large circle of 105°E longitude as the dividing line between the Eastern (to the east of the line) and Western Hemispheres. The Qinghai-Tibet Plateau is location at the intersection of the world's largest and most important north-south and east-west structures, and the Pamir Plateau is the backbone of regional structures. The Qinghai-Tibet Plateau originates from the Pamir Plateau, a thermal dome during the Indosinian period, which later transformed into an abnormal gravity column with a diameter of 200 km and sank 600 km vertically to form a vertical open-close structure to be completed in the Cretaceous period. From the Pamir Plateau at the center there are three horizontal compressional-extensional tectonics expanding to the east, and one to the west. During the Xishan period, the Pamir Plateau also experienced igneous intrusion, while its Cretaceous structure remained largely undeformed. In the Paleogene, the India-Asia collision formed the magnificent Himalayan orogenic belt that was first compressed and then uplifted. Expanding northward from the Himalayas three mantle branches rose during the Quaternary, causing the entire Qinghai-Tibet Plateau to rise. According to the deep dynamics model established in this article, the early stage of the plateau uplift is manly manifested by centrifugal movement of geological bodies in vertical direction and extensional movement in horizontal direction, and the later stage of mainly compression, is manifested by centripetal vertical movement and horizontal compression movement of geological bodies. In terms of driving force, thermal energy is the main driving force in the early stage and gravity potential energy in the later stage.

The uplift of the Qinghai-Tibet Plateau is the most remarkable geological event of the Cenozoic era within the Eurasian continent. It has direct impacts on the shallow lithosphere and the crust's surface layer through short- and long-range effects, affecting topography, energy and natural resources, ecology, environment, and geohazards closely related to human survival and development. Under the remote effects of the Qinghai-Tibet Plateau uplift the Baikal Lake Rift, the Fenwei Rift, and the East Africa Great Rift Valley are formed. Finally, five issues are briefly discussed: the naming and timing of the Indosinian movement; the timing of start/termination and types of the Indosinian movement; the Qinghai-Tibet Plateau being the best place to study various types of orogenic belts; the determination of the eastern and western tectonic structures of the Himalayan orogenic belt; and the exploration of the four-dimensional dynamics model of the Pamir Plateau.

Key words: Qinghai-Tibet Plateau, Pamir Plateau, geothermal energy, mantle branch, geodynamics, tectonic evolution, remote effects