CHAMPAIGN, Ill., Feb. 8 (UPI) -- U.S. geologists say they've located a large section of the Earth's crust that disappeared about 15 million years.
The University of Illinois researchers used seismic waves to find the massive block of rock beneath Tibet, thereby helping solve the mystery of how continents behave when they collide.
The Tibetan Plateau and adjacent Himalayan Mountains were created by the movements of vast tectonic plates that make up Earth's outermost layer of rocks -- the lithosphere.
According to the scientists, tectonic models of Tibet vary greatly, including ideas such as subduction of the Eurasian plate, subduction of the Indian plate and thickening of the Eurasian lithosphere. According to the last model, the thickened lithosphere became unstable, and a piece broke off and sank into the deep mantle.
Until recently, the theory lacked any clear observation to support it. Then Professor Wang-Ping Chen and doctoral student Tai-Lin Tseng found the missing rock.
"This remnant of detached lithosphere provides key evidence for a direct connection between continental collision near the surface and deep-seated dynamics in the mantle," Tseng said.
The study is to appear in the Journal of Geophysical Research.
