The Tibetan Plateau has an average elevation of ~4000-5000 m and is bound by the deserts of the Tarim and Qaidam basins to the north, the Himalaya to the south and Qingling mountains to the east. The Plateau is made up of a series of continental fragments that were amalgamated during the Palaeozoic (541-252 million years ago (Ma) and Mesozoic (252-66 Ma) during the collision between India and Eurasia, shown in Fig. 1. One theory suggests that the uplift of the plateau reached its current elevation around 8 Ma and is underlain by ~65 km of continental crust. The precise timing and nature of the uplift of the Tibetan Plateau though remains uncertain. There is evidence for synchronous uplift of the entire plateau, pulsed plateau uplift, and incremental outward and upward plateau growth (Molnar et al., 1993; Tapponnier et al., 2001; Rowley and Currie, 2006). Much more research is required over a wide area to properly constrain the history of the region.
Fig 1. Stevens et al. 2013 tectonic map of China.
More information about the geology of the Tibetan Plateau can be found here.
The landscapes within the plateau include wide grasslands (Fig 2), lakes (Fig 3) and steep valleys. (Fig 4)
Fig 2 - Near the first bend of the Yellow River and Maqu. View of a wide grassland where the locals were growing onions.
Fig 3 - Near Madou. View of lakes near 4000m
Fig 4 - In Qinghai Province. View on the way down into the Yellow River valley.
Bulk sample data of rare earth element (REE) concentrations from the Kunlun mountains on the northern edge of the Tibetan Plateau are similar to loess from Lanzhou (Clarke 1995). This suggests that potentially some loess is sourced from the plateau. Cosmogenic radionuclides from the loess combined with magnetic susceptibility suggest that the source of the loss is a cold, humid region. The Tibetan Plateau is a good potential source as wind patterns in the region would fit with transport from the region to the Loess Plateau (Maher & Thompson 1999; Maher et al. 2009).
Recent zircon U-Pb dating from Pullen et al. (2011) and Stevens et al. (2013) also suggest that the Tibetan Plateau is at least part of the source of the loess although the mechanisms of transport are still in contention, with our recent work suggesting the yellow River may be important (Stevens et al. 2013).
Molnar, P., England, P. & Martinpod, J. 1993. Mantle dynamics, uplift of the Tibetan Plateau, and the Indian Monsoon. Reviews of Geophysics, 31, 357-396.
Tapponnier, P., Zhiqin, X., Roger, F., Meyer, B., Arnaud, N., Wittlinger, G. & Jingsui, Y. 2001. Oblique Stepwise Rise and Growth of the Tibetan Plateau. Science, 294, 1671-1677.
Rowley, D. & Currie, B. 2006. Palaeo-altimetry of the late Eocene to Miocene Lunpola basin, central Tibet. Nature, 439, 677-681.
Clarke, M.L. 1995. A comparison of magnetic fabrics from loessic silts across the Tibetan front, Western China. Quaternary Proceedings, 4, 19-26.
Maher, B.A., Mutch, T.J. & Cunningham, D. 2009. Magnetic and geochemical characteristics of Gobi Desert surface sediments: Implications for provenance of the Chinese Loess Plateau. Geology, 37, 279-282.
Maher, B.A. & Thompson, R. 1999. Palaeomonsoons, I: The palaeoclimatic record of the Chinese loess and palaeosols, in Maher, B.A., and Thompson, R., eds., Quaternary climates, environments and magnetism: Cambridge, UK, Cambridge University Press, 81-125.
Pullen, A., Kapp, P., McCallister, A.T., Chang, H., Gehrels, G.E., Garzione, C.N., Heermance, R.V. & Ding, L. 2011. Qaidam Basin and northern Tibetan Plateau as dust sources for the Chinese Loess Plateau and palaeoclimatic implications. Geology, 39, 1031-1034.
Stevens, T., Carter, A., Watson, T.P., Vermeesch, P., Ando, S., Bird, A.F., Lu, H., Garzanti, E., Cottam, M. & Sevastjanova, I. 2013. Genetic linkage between the yellow River, the Mu Us desert and the Chinese Loess Plateau. Quaternary Science Reviews.