Japan Geoscience Union Meeting 2016

Presentation information

International Session (Poster)

Symbol S (Solid Earth Sciences) » S-CG Complex & General

[S-CG19] Hydrogen in the Earth's interior from the crust to the core

Mon. May 23, 2016 5:15 PM - 6:30 PM Poster Hall (International Exhibition Hall HALL6)

Convener:*Bjorn Mysen(Geophysical Laboratory, Carnegie Inst. Washington), Eiji Ohtani(Department of Earth and Planetary Materials Science, Graduate School of Science, Tohoku University), Toru Inoue(Geodynamics Research Center, Ehime University)

5:15 PM - 6:30 PM

[SCG19-P01] Effect of pressure on water solubility in aluminous bridgmanite

*Jiuhua Chen1,2, Martha G Pamato3, Toru Inoue4, Sho Kakizawa4, Bin Yang1, Yangting Lin5, Tomoo Katsura3, Takaaki Kawazoe3, Bingbing Liu6 (1.Florida International Univ., 2.Center for High Pressure Science and Technology, Changchun, 3.Bayerisches Geoinstitut, Universitaet, 4.Ehime University, 5.Institute of Geology and Geophysics, Chinese Academy of Sciences, 6.Jilin University)

We have conducted a sequence of high pressure experiments to study water solubility in aluminous bridgmanite as a function of pressure at 1900oC. The experimental high pressures were generated using multi-anvil presses at Bayerisches Geoinstitut (BGI) for pressures up to 28 GPa and at Geodynamics Research Center (GRC) for pressures above 30GPa. The starting material for these experiments was a mixture of oxides (Mg(OH)2, Al2O3 and SiO2) with equivalent of about 5 mol % of Al2O3 and 15 wt % of H2O. The structure and composition of the bridgmanite sample after high P/T syntheses were examined using x-ray diffraction (XRD) and electron probe microanalysis (EPMA). Water concentration in the sample was measured using secondary ion mass spectroscopy (SIMS) and Fourier transform infrared spectroscopy (FTIR). The measurements yield that the aluminous bridgmanite with about 2 wt% of Al2O3 may take as much as 0.13 wt % of H2O at the P/T condition of the top of the Earth’s lower mantle and this solubility increases significantly with pressure. At the bottom of Earth’s lower mantle, bridgmanite may take nearly a couple of weight percent of water according to simple extrapolation of the experiment result, indicating that the capacity of water reservoir of the lower mantle can be as large as a few to ten oceans of water.