The research team led by Prof. Motohiko Murakami of Tohoku University have revealed for the first time that the dense magmas in the Earth's interior become significantly "darker" with increasing pressure, and become less thermally conductive than previously expected. The results indicate that the possible presence of such dense and "dark" magmas at the bottom of the mantle play an essential role for the generation of giant hot mantle upwelling rooted in the Earth's core-mantle boundary, so-called "super-hot plume".
The research is published in the November 11, 2014 issue of*Nature Communications*.
Professor Motohiko Murakami
Department of Earth and Planetary Materials Science,Tohoku University
E-mail：motohiko*m.tohoku.ac.jp (Replace * with @)
Fig.1 TDistribution of Ultra-Low-Velocity Zones observed at the base of the mantle (red region).
Fig.2 Schematic cross section of the earth's mantle, showing the large hot mantle upwellings rooted in the core-mantle boundary.
Fig.3 Schematic image of the diamond anvil cell high-pressure apparatus.
Fig.4 Photomicrographic images of the sample under 2 GPa (left) and 80 GPa (right) in the diamond anvil cell.
Fig.5 Schematic image of the presence of the dark magmas at the bottom of the mantle.