TY - JOUR
T1 - Sound velocities of hydrous ringwoodite to 16GPa and 673K
AU - Mao, Zhu
AU - Lin, Jung Fu
AU - Jacobsen, Steven D.
AU - Duffy, Thomas S.
AU - Chang, Yun Yuan
AU - Smyth, Joseph R.
AU - Frost, Daniel J.
AU - Hauri, Erik H.
AU - Prakapenka, Vitali B.
N1 - Funding Information:
We thank I. Kantor and K. K. Zhuravlev for experimental assistance and A. Wheat for manuscript editing. Experiments performed at GeoSoilEnviroCARS (Sector 13), Advanced Photon Source (APS), Argonne National Laboratory, was supported by the National Science Foundation (NSF) through EAR-0622171 and U.S. Department of Energy ( DE-FG02-94ER14466 ). Use of the Advanced Photon Source was supported by the DOE, Office of Science, Office of Basic Energy Sciences , under Contract No. DE-AC02-06CH11357. Support for Brillouin scattering and gas loading equipment was provided by GSECARS and COMPRES, the Consortium for Materials Properties Research in Earth Sciences under NSF Cooperative Agreement EAR 10-43050 . This research was supported by the NSF grants EAR-0838221 and EAR-1056670 to J.F. Lin, EAR-0748707 to S.D. Jacobsen, EAR-0738510 to T.S. Duffy, and EAR07-11165 and 11-13369 to J.R. Smyth. Additional support was provided by the Carnegie/DOE Alliance Center (CDAC) and Energy Frontier Research in Extreme Environments (EFree) to J.F. Lin, and by the David and Lucile Packard Foundation to S.D. Jacobsen.
PY - 2012/5/15
Y1 - 2012/5/15
N2 - To understand the effect of hydration on the sound velocities of major mantle minerals and to constrain the mantle's H 2O budget, we have measured the single-crystal elastic moduli of hydrous ringwoodite, (Mg 1.633Fe 2+ 0.231Fe 3+ 0.026)Si 1.00H 0.179O 4 with 1.1wt.% H 2O using Brillouin scattering combined with X-ray diffraction in an externally-heated diamond anvil cell up to 16GPa and 673K. Up to 12GPa at 300K, the presence of 1.1wt.% H 2O lowers the elastic moduli of ringwoodite by 5-9%, but does not affect the pressure derivatives of the elastic moduli compared to anhydrous ringwoodite. The reduction caused by hydration is significantly enhanced when temperatures are elevated at high pressures. At 12GPa, increasing temperature by δT=100K leads to a 1.3-2.4% reduction in the elastic moduli (C 11, C 12, and C 14). Comparing our results with seismic observations, we have evaluated the potential H 2O content in the lower part of the transition zone. Our results indicate that the observed seismic velocity anomalies and related depth depression of the 660-km discontinuity could be attributed to thermal variations together with the presence of ~0.1wt.% H 2O.
AB - To understand the effect of hydration on the sound velocities of major mantle minerals and to constrain the mantle's H 2O budget, we have measured the single-crystal elastic moduli of hydrous ringwoodite, (Mg 1.633Fe 2+ 0.231Fe 3+ 0.026)Si 1.00H 0.179O 4 with 1.1wt.% H 2O using Brillouin scattering combined with X-ray diffraction in an externally-heated diamond anvil cell up to 16GPa and 673K. Up to 12GPa at 300K, the presence of 1.1wt.% H 2O lowers the elastic moduli of ringwoodite by 5-9%, but does not affect the pressure derivatives of the elastic moduli compared to anhydrous ringwoodite. The reduction caused by hydration is significantly enhanced when temperatures are elevated at high pressures. At 12GPa, increasing temperature by δT=100K leads to a 1.3-2.4% reduction in the elastic moduli (C 11, C 12, and C 14). Comparing our results with seismic observations, we have evaluated the potential H 2O content in the lower part of the transition zone. Our results indicate that the observed seismic velocity anomalies and related depth depression of the 660-km discontinuity could be attributed to thermal variations together with the presence of ~0.1wt.% H 2O.
KW - Brillouin scattering
KW - High pressure-temperature
KW - Hydrous ringwoodite
KW - Single-crystal elasticity
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U2 - 10.1016/j.epsl.2012.03.001
DO - 10.1016/j.epsl.2012.03.001
M3 - Article
AN - SCOPUS:84860542358
VL - 331-332
SP - 112
EP - 119
JO - Earth and Planetary Science Letters
JF - Earth and Planetary Science Letters
SN - 0012-821X
ER -