Cenozoic sedimentary records and geochronological constraints of differential uplift of the Qinghai-Tibet Plateau

Abstract

Geological mapping data (1:250000) in the Qinghai-Tibet Plateau and its adjacent regions reveal the sediment sequences, distribution and tectonic evolution of the 92 Tertiary remnant basins. SouthernTibet and the Yecheng area in Xinjiang, located at southern and northwestern margins of the Qinghai-Tibet Plateau, respectively, were parts of the Neo-Tethys remnant sea in the Paleogene. In southern Tibet, both the subabyssal and abyssal sequences occur at the Gyangze, Saga, Guoyala, and Sangmai areas. The deep-water facies successions outcrop in the west, whereas the shallow-water facies sequences in the east, indicating the east to the west retreat of the Neo-Tethys Ocean. The retreat of the Neo-Tethys Ocean in the east was contributed to the earlier tectonic uplift of the eastern Qinghai-Tibet Plateau. The uplift process of the Plateau from the Late Cretaceous to Pliocene is described as follows: During the Late Cretaceous, tectonic uplift of the Qinghai-Tibet Plateau occurred in the northeastern part and the configuration of the Qinghai-Tibet Plateau was characterized by rise in the northeast and depression in the west. In the Paleocene-Eocene interval, the Tengchong-Baingoin and Kuyake-Golmud areas experienced local tectonic uplifting, the West Kunlun uplift zone broadened easterly, the Qilian uplift zone broadened southerly, and the Songpan-Garzê uplift zone shrank easterly. The Oligocene configuration of the Qinghai-Tibet Plateau was characterized by mountain chains rising along its margins and sedimentary basins in the central part because of tectonic uplifts of the Gangdisê and the Himalaya blocks. Meanwhile, the Kunlun-Altyn-Qilian uplift zones have also broadened southerly and northerly. In contrast, the great uplift zones of the Gangdisê, the Himalaya, the Karakorum, and the Kunlun blocks characterize the paleogeographic contours of the Qinghai-Tibet Plateau during the Miocene-Pliocene. Additionally, the thermochronological data on tectonic uplift events in southern Tibet, West Kunlun Mountains, Altyn Tagh, eastern Tibet, and western Sichuan all suggest that the most intense deformation occurred at 13-8 Ma and since 5 Ma, respectively, corresponding to two great uplift periods in Neogene. As a result, turnover of paleogeographic configuration of the Qinghai-Tibet Plateau occurred during the Neogene, experiencing a change from high contours in the east in the pre-Oligocene to high contours in the west at the end-Pliocene. The uplift of the Qinghai-Tibet Plateau during the Cenozoic was episodic, and the uplifts of various blocks within the Plateau were spatially and chronologically different.

Climatic and tectonic uplift evolution since ~7 Ma in Gyirong basin, southwestern Tibet plateau: clay mineral evidence

“…smectite) in the period of 7.0-5.8 Ma BP indicate warm and humid climatic conditions. The increasing abundance of illite and chlorite and the relative high-illite crystallinity in the period of 5.8-5.5 Ma BP suggest relative cool and dry paleoclimate conditions, but stronger physical erosion in comparison with the early stage, and the subsequent decrease in illite and chlorite content and illite crystallinity is indicative of relative warm and humid climate prevailed (Zhang et al 2008) during the period of 5.5-2.5 Ma BP. A much warmer condition was indicated from 2.5 to 1.7 Ma BP in Gyirong basin.…”

“…Investigation of depositional sequences in the 92 remnant sedimentary basins in Tibetan plateau suggested that during Paleocene-Eocene local tectonic uplifting took place along the zone of Tengchun-Bange-Zhada, and the Gyirong region rose and started erosion since *34 Ma (Zhang et al 2008). The distribution of erosion and sediment areas around the Gyirong region during the Oligocene time was shown in Fig.…”

Paleogene-Neogene stratigraphic realm and sedimentary sequence of the Qinghai-Tibet Plateau and their response to uplift of the plateau

“…2003 ( Figure 1). These small basins are common in the following aspects: (1) they are distributed as a long and narrow strip with a small area along fault zone; (2) the deposition in the basin began with the rapid accumulation of conglomerates, sandstones of alluvial fan-fluvial facies, then the mudstones, marls, siltstones intercalated with limestones, muddy gypsums of lacustrine facies, and finally ended with the sandstones and conglomerate of fluvial-alluvial fan facies; (3) the deposits in the basin are in a huge thickess, commonly more than 1000 m thick; (4) there are volcanic rocks in some basins [34,35].…”

“…Since the late Neogene, the Qinghai-Tibet Plateau is characterized by the large-scale uplift of mountains [4,34,35], and some of the Paleogene-Neogene basins have been uplifted to their peak. Because of the erosion effect, some sediment record is absent in these basins.…”

Characteristics of Later Different Reformation and its Significance in Occurrence of Multi-Energy Deposits in Ordos Basin

“…It has been indicated that the Tibet Plateau has gradually uplifted in late Miocene and Pliocene and the uplift has influenced surrounding areas, as recorded in the Qilian Mountain, Jiuxi Basin and Linxia Basin (Song et al, 2001). Age of the uplift has been indicated at 13-8 Ma and 5 Ma (Zhang et al, 2008), however, it is also argued that the uplift happened in 3.6-1.7 Ma, corresponding to the Tibet Movement (Li et al, 1996;Fang et al, 1997). The uplift of the Tibet Plateau has influenced the west Ordos Basin, and has caused and intensified as well the east-west structural reverses.…”