SCIENCE - New model reveals multiple compositional components of Earth's deep mantle being carried up to the surface

Seeking to better understand the composition of the lowermost part of Earth's mantle, located nearly 2,900 kilometers (1,800 miles) below the surface, a team of Arizona State University researchers has developed new simulations that depict the dynamics of deep Earth. A paper published March 30 in Nature Geoscience reports the team's findings, which could be used to explain the complex geochemistry of lava from hotspots such as Hawaii ...

http://phys.org/news/2014-03-reveals-multiple-compositional-components