Lin, Jung-Fu and Jacobsen, Steven D. and Sturhahn, Wolfgang and Jackson, Jennifer M. and Zhao, Jiyong and Yoo, Choong-Shik (2006) Sound velocities of ferropericlase in the Earth's lower mantle. Geophysical Research Letters, 33 (22). Art. No. L22304. ISSN 0094-8276 http://resolver.caltech.edu/CaltechAUTHORS:20130304-101257261
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Sound velocity measurements on candidate mantle minerals at relevant mantle conditions are needed to interpret Earth's seismic structure in terms of model abundances, variable composition, and other potentially influential parameters such as electronic spin-pairing transitions. Here the sound velocities of the lower-mantle ferropericlase have been measured by nuclear resonant inelastic X-ray scattering to 110 GPa. Compressional and shear wave velocities and their pressure derivatives rise dramatically across the spin-pairing transition of iron in (Mg_(0.75)Fe_(0.25))O above 50 GPa. Effects of the transition on the sound velocities of (Mg, Fe)O at lower-mantle pressures yield values that are much greater than what is predicted by studying pure MgO and high-spin ferropericlase. Our results indicate that sound velocities of the low-spin ferropericlase need to be considered in future geophysical and geochemical models, which could offset the effect of the addition of iron in the lower-mantle minerals and affect the evaluation of the lower-mantle heterogeneities.
|Additional Information:||© 2006 by the American Geophysical Union. Received 6 September 2006; revised 6 October 2006; accepted 18 October 2006; published 18 November 2006. We acknowledge XOR-3, APS, ANL for the use of the synchrotron facilities and HPCAT for the use of the ruby system. We thank V. V. Struzhkin, Y. Fei, V. Iota, and H. C. Cynn for their fruitful discussions. We wish to thank E. E. Alp for designing the new Be gaskets. This work and use of the APS are supported by U.S. DOE, Basic Energy Sciences, Office of Science, under contract W-31-109-ENG-38, and the State of Illinois under HECA. This work at LLNL was performed under the auspices of the U.S. DOE by University of California and LLNL under contract W-7405-Eng-48. J.F.L. is also supported by the Lawrence Livermore Fellowship. S.D.J. acknowledges financial support from NSF EAR-0440112, a Carnegie Fellowship and CDAC.|
|Subject Keywords:||ferropericlase; spin transition; sound velocities|
|Official Citation:||Lin, J.-F., S. D. Jacobsen, W. Sturhahn, J. M. Jackson, J. Zhao, and C.-S. Yoo (2006), Sound velocities of ferropericlase in the Earth’s lower mantle, Geophys. Res. Lett., 33, L22304, doi:10.1029/2006GL028099|
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|Deposited By:||Tony Diaz|
|Deposited On:||05 Mar 2013 00:03|
|Last Modified:||05 Mar 2013 00:03|
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