New study suggests that the rise of one of the highest places on Earth, the Tibetan plateau, has began much earlier than previously assumed. “Our study suggests that high topography began to develop as early as 30 million years ago, and perhaps was present even earlier,” said Eric Kirby, associate professor of geoscience at Pennsylvania State. Most researchers have thought that the high topography in eastern Tibet had developed during the past 10 to 15 million years, as the deep crust beneath the central Tibetan Plateau had flowed to the surface, thickening the Earth’s crust and causing the area to rise, Kirby explained. Kirby and his team took samples from the hanging wall of the Yingxiu-Beichuan fault, the primary fault responsible for the 2008 Wenchuan earthquake in Sichuan. They also applied a variety of radioactive dating methods to unravel the timeline of the region, and find clues to when specific rocks were lifted. According to the results published in Nature Geoscience, the rocks in the area were formed about 30 to 50 million years ago.
After the collision of the Indian and Eurasian plates that was initiated about 50 million years ago, portions of the Tibetan plateau began to lift, researchers claimed.The results also suggested that gradual cooling during this time was followed by two episodes of rapid erosion, one which happened 30 to 25 million years ago and the second which started 15 to 10 million years ago and continues through to today. “We are still a long way from completely understanding when and how high topography in Asia developed in response to India-Asia collision,” Kirby stressed. The Tibetan Plateau, also called ‘the Roof of the World’, with an average elevation of about 16,000 feet (4,900 meters) lies at the intersection of the most vigorous collision of continental plates on the planet, where the Indian continental plate rams into the Eurasian plate and dives beneath it. FGP/PKH