Asian Scientist – By Sukanya Charuchandra
AsianScientist (Apr. 5, 2022)– The lofty Himalayas and the Tibetan plateau formed when the Eurasian and Indian continental plates collided. These plates are large independently moving tracts of the Earth’s surface. A new study reports that the Indian continental plate likely tilts downward under the Asian plate. Published in Proceedings of the National Academy of Sciences, these results, based on a helium signature found in more than 200 hot springs across the Tibetan plateau, oppose a widely believed model for mountain building, according to which the Indian plate simply lies flat under the Asian plate. Better idea about the arrangement of these plates will help scientists understand the continental collision from eons ago.
Some 50 million years ago, the Indian and Asian continental plates collided, leading to the formation of the Himalayas and not long after, the Tibetan plateau. But how the plates interface has long been debated. Beginning 1920s, several theories have been proposed but two came to be the most prominent. In the first, the Indian plate is thought to lie flat under Tibet, which is a part of the Asian plate. Whereas the other model says that the Indian plate tilts under the Asian plate, sloping downwards below Tibet.
Researchers from the United States and China, led by Simon Klemperer of the Department of Geophysics at Stanford University, wanted to see which of the two models accurately explain how the highest mountains came to be.
Over many years, Klemperer’s team sampled water and gas from 196 geothermal springs in the Tibetan plateau and included previously reported data from 29 other Tibetan springs. Ranging from hot to cool, the springs were dispersed across the plateau. They bring water from tens of kilometres underground to the surface. With the water, they carry elements such as helium. The researchers trapped water and gas from these springs in copper tubes, through which helium cannot escape.
Helium gas is a good “proxy to the process” of geological changes in Tibet, Shyam Rai, of the Indian Institute of Science Education and Research, Pune, told Asian Scientist. Rai who is an Emeritus Professor at the Department of Earth and Climate Science of the institute was not involved in the study. Click here to read more.