Breaking research news from a team of scientists led by
Carnegie’s Ho-kwang “Dave” Mao reveals that the composition of the Earth’s
lower mantle may be significantly different than previously thought. These
results are to be published by Science.
The lower mantle comprises 55 percent of the planet by
volume and extends from 670 and 2900 kilometers in depth, as defined by the
so-called transition zone (top) and the core-mantle boundary (below). Pressures
in the lower mantle start at 237,000 times atmospheric pressure (24
gigapascals) and reach 1.3 million times atmospheric pressure (136 gigapascals)
at the core-mantle boundary.