The Himalayan-Tibetan orogen was created by the Indo-Asian collision over the past 70-50 Ma. Significant crustal shortening (at least 1400 km) which leads to eventual construction of the Cenozoic Tibet Plateau, began more or less synchronously in the Eocene (50-40 Ma) (figure 1). The orogen, which is the youngest and most spectacular active continent collisional belt on Earth, has long been known as the golden key to the global orogenic mechanism, and the natural laboratory for  continental dynamics theory.
        Tibet is the largest, highest and flattest plateau in Earth with an average elevation exceeding 5000 m. It is bound by the deserts of the Tarim and Qaidam Basins to the north, the Himalayan, Karakoram, and Pamir mountain chains to its south and west but its eastern margin is more diffuse (figure 2). The Tibetan plateau was uplifted more than 4 km and the crust under the central part of it has thickened up to 70 km (double the thickness of most continental crust). Although several models have tried to explain how such topography formed, we still have much to learn.

Figure 1. A simplified map showing                                                      Figure 2. Digital elevation map of the Himalayan-Tibetan orogen.
 the position India in relation to
Eurasia at various times [USGS].


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