@article{7af92561cea54b248a077df36b7caec6,
title = "Possible H2O storage in the crystal structure of CaSiO3 perovskite",
abstract = "The lower mantle is believed to contain much less hydrogen (or H2O) because of the low storage capacity of the dominant mineral phases, such as bridgmanite and ferropericlase. However, possible hydrogen storage in the third most abundant mineral in the region, CaSiO3 perovskite (Ca-Pv), is not well unknown. We have synthesized Ca-Pv from different starting materials with varying H2O contents at 19–120 GPa and 1400–2200 K in laser-heated diamond-anvil cell. While cubic perovskite structure is stable at the mantle-related pressures-temperatures (P−T) in anhydrous systems, we found non-cubic diffraction peak splitting in Ca-Pv even at high temperatures when it is synthesized from hydrous starting materials. In-situ high-pressure infrared spectroscopy showed OH vibration possibly from Ca-Pv. The unit-cell volume of hydrothermally synthesized Ca-Pv is systematically smaller than that of anhydrous Ca-Pv at high pressures. These observations suggest possible H2O storage in Ca-Pv at mantle-related P−T conditions. We also found the formation of separate δ–AlOOH and Ca-Pv phases from Al-bearing CaSiO3 glass starting materials in an H2O medium at 60 GPa and 1400 K. Ca-Pv still showed non-cubic peak splitting at high temperatures in this experiment. Therefore, it is possible that hydrous phases may coexist together with hydrous Ca-Pv in the lower mantle.",
keywords = "CaSiO perovskite, Mantle, Water",
author = "H. Chen and K. Leinenweber and V. Prakapenka and C. Prescher and Y. Meng and H. Bechtel and M. Kunz and Shim, {S. H.}",
note = "Funding Information: We thank an anonymous reviewer and the editor for the comments and suggestions. The work has been supported by the NSF (EAR-1338810 and EAR-1725094) and NASA (80NSSC18K0353). H. C. and S.-H.S. were supported by a Keck grant (PI: P. Buseck). The results reported herein benefit from collaborations and information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. The synchrotron experiments were conducted at GSECARS (University of Chicago, Sector 13) and HPCAT (Sector 16), Advanced Photon Source (APS). GSECARS is supported by the NSF-Earth Science (EAR-1128799) and DOE-GeoScience (DE-FG02-94ER14466). HPCAT is supported by DOE-NNSA (DE-NA0001974) and DOE-BES (DE-FG02-99ER45775). APS is supported by DOE-BES under contract DE-AC02-06CH11357. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We acknowledge the use of facilities within the Eyring Materials Center at Arizona State University. The experimental data for this paper are available by contacting SHDShim@asu.edu. Funding Information: We thank an anonymous reviewer and the editor for the comments and suggestions. The work has been supported by the NSF ( EAR-1338810 and EAR-1725094 ) and NASA ( 80NSSC18K0353 ). H. C. and S.-H.S. were supported by a Keck grant (PI: P. Buseck). The results reported herein benefit from collaborations and information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. The synchrotron experiments were conducted at GSECARS (University of Chicago, Sector 13) and HPCAT (Sector 16), Advanced Photon Source (APS). GSECARS is supported by the NSF-Earth Science ( EAR-1128799 ) and DOE -GeoScience ( DE-FG02-94ER14466 ). HPCAT is supported by DOE-NNSA ( DE-NA0001974 ) and DOE-BES ( DE-FG02-99ER45775 ). APS is supported by DOE-BES under contract DE-AC02-06CH11357 . This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231. We acknowledge the use of facilities within the Eyring Materials Center at Arizona State University. The experimental data for this paper are available by contacting SHDShim@asu.edu. Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",
year = "2020",
month = feb,
doi = "10.1016/j.pepi.2019.106412",
language = "English (US)",
volume = "299",
journal = "Physics of the Earth and Planetary Interiors",
issn = "0031-9201",
publisher = "Elsevier",
}