scispace - formally typeset
Search or ask a question

Showing papers by "Motohiko Murakami published in 2002"

Journal Article•DOI•
Water in Earth's lower mantle.

[...]

Motohiko Murakami1, Kei Hirose1, Hisayoshi Yurimoto1, Satoru Nakashima1, Naoto Takafuji1 •
Tokyo Institute of Technology1
08 Mar 2002-Science
TL;DR: Secondary ion mass spectrometry measurements show that Earth's representative lower mantle minerals synthesized in a natural peridotitic composition can dissolve considerable amounts of hydrogen.
Abstract: Secondary ion mass spectrometry measurements show that Earth's representative lower mantle minerals synthesized in a natural peridotitic composition can dissolve considerable amounts of hydrogen. Both MgSiO3-rich perovskite and magnesiowustite contain about 0.2 weight percent (wt%) H2O, and CaSiO3-rich perovskite contains about 0.4 wt% H2O. The OH absorption bands in Mg-perovskite and magnesiowustite were also confirmed with the use of infrared microspectroscopic measurements. Earth's lower mantle may store about five times more H2O than the oceans.

174 citations

Journal Article•DOI•
Post-stishovite phase boundary in SiO2 determined by in situ X-ray observations

[...]

Shigeaki Ono1, Shigeaki Ono2, Kei Hirose2, Motohiko Murakami2, Maiko Isshiki •
Japan Agency for Marine-Earth Science and Technology1, Tokyo Institute of Technology2
15 Apr 2002-Earth and Planetary Science Letters
TL;DR: In this article, a laser heating diamond anvil cell experiment, with an angle-dispersive X-ray diffraction using synchrotron radiation source at the SPring-8, has been developed to observe the phase transition in silica (SiO2) between the P42/mnm (rutile-type) and Pnnm (CaCl2-type), up to pressures of 100 GPa and at temperatures up to 2200 K.

98 citations