Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 2006 | Supplemental Material + Published
Journal Article Open

Single-crystal elasticity and sound velocities of (Mg_(0.94)Fe_(0.06))O ferropericlase to 20 GPa

Abstract

The single-crystal elastic properties of high-spin (Mg_(0.94)Fe_(0.06))O ferropericlase were measured by Brillouin spectroscopy on a sample compressed to 20 GPa with diamond anvil cells using methanol-ethanol-water as a pressure-transmitting medium. At room pressure, the adiabatic bulk (K_0S) and shear (μ_0S) moduli are K_0S = 163 ± 3 GPa and μ_0S = 121 ± 2 GPa, in excellent agreement with ultrasonic results from the same bulk sample (Jacobsen et al., 2002). A fit to all our high-pressure Brillouin data using a third-order finite-strain equation of state yields the following pressure derivatives of the adiabatic bulk and shear moduli: K′_0S = 3.9 ± 0.2 and μ′_0S = 2.1 ± 0.1. Within the uncertainties, we find that K_0S and K′_0S of (Mg_0.94)Fe_(0.06))O are unchanged from MgO. However, μ_0S and μ′_0S of (Mg_(0.94)Fe_(0.06))O are reduced by 8% and 11%, respectively. The aggregate compressional (VP) and shear (VS) wave velocities are reduced by 4% and 6%, respectively, as compared to MgO. The pressure dependence of the single-crystal elastic moduli and aggregate sound velocities is linear within the investigated pressure range. The elastic anisotropy of (Mg_(0.94)Fe_(0.06))O is about 10% greater than that of MgO at ambient conditions. At the highest pressure obtained here, the elastic anisotropy of (Mg_(0.94)Fe_(0.06))O is close to zero. On the basis of our measurements and earlier ultrasonic measurements, we find that the pressure derivatives of shear moduli obtained at room pressure for low iron concentrations (<20 mol% FeO) of high-spin ferropericlase are inconsistent with those inferred from the lower mantle PREM model.

Additional Information

© 2006 American Geophysical Union. Received 15 September 2005; revised 25 January 2006; accepted 6 March 2006; published 7 September 2006. We would like to thank C. Sanchez-Valle, W. Sturhahn, W.-P. Chen, X. Song, D. L. Lakshtanov, M. Roskosz, and J.-F. Lin for helpful discussions. Our manuscript benefited from comments made by I. Jackson and an anonymous reviewer. This research was funded in part by National Science Foundation grants EAR 0003383 (J. D. B.) and The Elasticity Grand Challenge project (EAR 0135642, to J. D. B.). J. M. J. also acknowledges the support of the MSA Grant for Student Research in Mineralogy and Petrology and a Carnegie Fellowship. S. D. J. is supported by NSF EAR-0440112, CDAC, and by a Carnegie Fellowship.

Attached Files

Published - Jackson_etal2006_2005JB004052.pdf

Supplemental Material - jgrb14719-sup-0001-t01.txt

Supplemental Material - jgrb14719-sup-0002-t02.txt

Files

jgrb14719-sup-0002-t02.txt
Files (446.6 kB)
Name Size Download all
md5:c2e697e998be705f3a77f7cbcec7de27
711 Bytes Preview Download
md5:15495fa406c70e06c37290bc795f9768
2.3 kB Preview Download
md5:4e41ae157b2488ea5328dabe25964de4
443.5 kB Preview Download

Additional details

Created:
August 22, 2023
Modified:
October 26, 2023