Report

Electrical Conductivity of Olivine, Wadsleyite, and Ringwoodite Under Upper-Mantle Conditions

+ See all authors and affiliations

Science  29 May 1998:
Vol. 280, Issue 5368, pp. 1415-1418
DOI: 10.1126/science.280.5368.1415

You are currently viewing the abstract.

View Full Text

Via your Institution

Log in through your institution

Log in through your institution


Abstract

Geophysical models show that electrical conductivity in Earth's mantle rises about two orders of magnitude through the transition zone in the depth range 410 to 660 kilometers. Impedance measurements obtained on Mg1.8Fe0.2SiO4 olivine, wadsleyite, and ringwoodite at up to 20 gigapascals and 1400°C show that the electrical conductivities of wadsleyite and ringwoodite are similar and are almost two orders of magnitude higher than that of olivine. A conductivity-depth profile to 660 kilometers, based on these laboratory data, shows a conductivity increase of almost two orders of magnitude across the 410-kilometer discontinuity; such a profile favors a two-layer model for the upper mantle. Activation enthalpies of 1.2 to 1.7 electron volts permit appreciable lateral variations of conductivity with lateral temperature variations.

  • * To whom correspondence should be addressed. E-mail: yousheng.xu{at}uni-bayreuth.de

  • On leave from Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

View Full Text

Related Content