Electrical conductivity of orthopyroxene and its high pressure phases

Electrical conductivity of orthopyroxene, clinopyroxene, and ilmenite + garnet with the same starting material San Carlos orthopyroxene (Mg0.92Fe0.08)SiO3 containing 2.89% Al2O3 by weight were measured within their respective stability fields in a multi‐anvil press. In the formula for conductivity σ=σ0 exp(−ΔH/kT), pre‐exponential factors σ0 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.