27 August 2015

3-D maps illustrate formation of the Hangai Dome in central Mongolia

Posted by lcooper

By Leigh Cooper

Researchers at Rice University, the University of Toronto, and Princeton University generated 3-D maps of the Earth under the Hangai Dome in central Mongolia from seismic data.

“Hangai Dome is one of the most bizarre high-elevation places in continental interiors on Earth,” said Min Chen, a postdoctoral research associate with the Department of Earth Science at Rice University in Houston, Texas. “There have been debates on mechanisms that caused the uplift of Hangai Dome, whether it’s driven by the movement of tectonic plates or caused by the hot mantle rock rising from the deeper Earth.”

The 3-D image below shows the earth under the dome. Colored yellow, warm rock rises up from the deep mantle toward the Earth’s surface. The pressure on the rock drops as it rises. When the rock reaches 150 kilometers (93 miles) below the surface, it starts to melt and form magma, illustrated in red. Heat released by the magma modifies the rigid outer layer of the Earth that becomes lighter and rises up, creating the Hangai Dome.

The scientists used 1.7 million seismic wave measurements from 227 earthquakes across East Asia in their computer simulations to create 3-D images of subsurface rock formations. From these maps, they will be able to answer questions about the tectonic evolution of surface landforms and identify subsurface structures that may pose earthquake hazards. The simulations and data processing were done using XSEDE (Extreme Science and Engineering Discovery Environment) supercomputers at the Texas Advanced Computing Center at the University of Texas at Austin and the DAVinCI supercomputer at Rice University.

“This unique example of continental uplift shows that the active mantle also plays an important role in shaping the Earth’s landscape and consequently the ecological habitat,” said Chen, who is lead author of a new study in Geophysical Research Letters, a journal of the American Geophysical Union.

The researchers published more information detailing East Asia’s crust and mantle in the March 2015 issue of  the American Geophysical Journal, Journal of Geophysical Research: Solid Earth.

— Leigh Cooper is a science writing intern at AGU.