title: Low core-mantle boundary temperature inferred from the solidus of pyrolite.
abstract: The melting temperature of Earth's mantle provides key constraints on the thermal structures of both the mantle and the core. Through high-pressure experiments and three-dimensional x-ray microtomographic imaging, we showed that the solidus temperature of a primitive (pyrolitic) mantle is as low as 3570 ± 200 kelvin at pressures expected near the boundary between the mantle and the outer core. Because the lowermost mantle is not globally molten, this provides an upper bound of the temperature at the core-mantle boundary (T(CMB)). Such remarkably low T(CMB) implies that the post-perovskite phase is present in wide areas of the lowermost mantle. The low T(CMB) also requires that the melting temperature of the outer core is depressed largely by impurities such as hydrogen.
authors.affiliation: Department of Earth and Planetary Sciences, Tokyo Institute of Technology, Meguro, Tokyo 152-8551, Japan.
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Nomura
authors.forename: Kei
authors.initials: K
authors.lastname: Hirose
authors.forename: Kentaro
authors.initials: K
authors.lastname: Uesugi
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ohishi
authors.forename: Akira
authors.initials: A
authors.lastname: Tsuchiyama
authors.forename: Akira
authors.initials: A
authors.lastname: Miyake
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Ueno