Landslide Lake in Tibet
A University of Alberta physicist who helped solve the age-old mystery of what keeps the highest plateau on Earth afloat, has added more pieces to the Tibetan puzzle. Dr. Martyn Unsworth has uncovered new research about the Tibetan Plateau-an immense region that for years has plagued researchers studying how the area became so elevated.
Several years ago, Unsworth and a team of researchers from China and the United States used low-frequency radio waves to determine that the mid-crust of the plateau is like "a big waterbed." The hot, molten rocks supporting the plateau are less dense than cold rocks, which means they rise up slowly, similar to how a hot-air balloon works. The discovery provides an explanation for how the whole of Tibet could rise up over millions of years.
After that finding, Unsworth returned to Tibet and has since learned that this geological make-up is typical of the whole length of the Himalayas, not just a small region. "We initially thought that this layer might be a local structure, but it's not so," said Unsworth, a professor in the U of A Faculty of Science. His research results are published in the current edition of the scientific journal, Nature.
Dubbed "the roof of the world," or the "abode of the Gods," the plateau contains not only Mount Everest but also all of the world's territory higher than 4,000 metres. The area was formed when India rammed into Asia about 50 million years ago and is considered a showcase of plate tectonics. Eventhough a number of theories have been proposed to explain the unusual thickness of the plateau-its crust doubles the average 30 to 35-kilometre thickness found the world over-little concrete evidence has been offered. Tibet was closed to foreign access until the 1980s, when French and Chinese researchers collaborated to investigate the plateau. Since then, Unsworth and his international research team have made a number of significant findings, and access to data collected in India was recently negotiated.
These newest results have allowed Unsworth and his research team to quantify how much flow, or viscosity, is taking place. "These models are important because they give observations that constrain a number of theories about what happens when mountains are formed," said Unsworth. "This has implications in a number of areas of Earth science, since all continents were formed in the past by a series of continent-continent collisions".
In Canada, for example, we cannot easily study collisions that occurred in the distant past, said Unsworth, but we can look at these geological processes where they are active today. Last summer he began a similar project in Eastern Turkey, where two plates are colliding. This collision zone is at an earlier stage than Tibet and may give some clues about the temporal evolution, he believes.
This work was supported by the U.S. National Science Foundation, the Ministry of Land and Resources of China, the Ministry of Education of China, the National Science Foundation of China, the Natural Sciences and Engineering Research Council of Canada and the Alberta Ingenuity Fund.
Posted By: Jaison