Paleoaltimetry reconstructions of the Tibetan Plateau: progress and contradictions

Over the last two decades, many quantitative paleoaltimetry reconstructions of the Tibetan Plateau have been published, but they are still preliminary and controversial, although several approaches have been combined paleontology and geochemistry, including vertebrate, plant, and pollen fossils as well as oxygen, carbon, and hydrogen isotopes. The Tibetan Plateau is the youngest and highest plateau on Earth, and its paleoaltimetry reconstructions are crucial to interpret its geodynamic evolution and to understand the climatic changes in Asia. Uplift histories of the Tibetan Plateau based on different proxies differ considerably, and two viewpoints are pointedly opposing on the paleoaltimetry estimations of the Tibetan Plateau. One viewpoint is that the Tibetan Plateau did not strongly uplift to reach its modern elevation until the Late Miocene, but another one, mainly based on stable isotopes, argues that the Tibetan Plateau formed early during the Indo-Asian collision and reached its modern elevation in the Paleogene or by the Middle Miocene. With either a geochemical or paleontological approach, the present is used as the key to the past. However, there are great difficulties because modern processes of isotopic fractionation and species for creature distribution are not easily precisely determined. In addition, the climatic and environmental backgrounds of past geological times have massive differences from the present, and associated adjustments are influenced by many human factors. In the future work, the applications of multidisciplinary comprehensive methods and cross-checks of their results will be productive, and we look forward to achieving more reliable estimates for paleoelevations of the Tibetan Plateau.