Isolated high, flat surfaces in the northwest Himalaya may be remnants of the Tibetan plateau, suggests a paper online in Nature Geoscience. These surfaces seem to have persisted over the past 40 million years, confirming that the plateau formed soon after the India?Asia continental collision.
Peter van der Beek and colleagues studied the landscape of northwest Himalaya and the western Tibetan plateau, identifying broad, high regions beyond the western margin of the Tibetan plateau. They found that these surfaces had been eroded very slowly over tens of millions of years ? in marked contrast with prominent Himalayan peaks, but similar to the western Tibetan plateau. This similarity to the erosion history of the Tibetan plateau indicates that in the past, the plateau must have extended further than its current western boundary.
The greater Tibetan plateau probably began disintegrating around 20 million years ago, when Himalayan deformation intensified, altering drainage patterns and leading to incision of the plateau.