Electrical conductivity of orthopyroxene and its high pressure phases

Abstract

Electrical conductivity of orthopyroxene, clinopyroxene, and ilmenite + garnet with the same starting material San Carlos orthopyroxene (Mg 0.92 Fe 0.08)SiO 3 containing 2.89 % Al 2 O 3 by weight were measured within their respective stability fields in a multi-anvil press. In the formula for conductivity σ = σ 0 exp(-ΔH/kT), pre-exponential factors σ 0 of orthopyroxene, clinopyroxene, and ilmenite + garnet are 5248, 1778, 2239 S/m, respectively, and the activation enthalpies are 1.80, 1.87 and 1.66 eV, respectively. These results are required for defining a laboratory-based conductivity-depth profile of the upper mantle.