The effect of chemical composition and oxygen fugacity on the electrical conductivity of dry and hydrous garnet at high temperatures and pressures

摘要

The in situ electrical conductivity of hydrous garnet samples (Py_(20)Alm_(76)Grs_4-Py_(73)Alm_(14)Grs_(13)) was determined at pressures of 1.0-4.0 GPa and temperatures of 873-1273 K in the YJ-3000t apparatus using a Solartron-1260 impedance/gain-phase analyzer for various chemical compositions and oxygen fugacities. The oxygen fugacity was controlled by five solid-state oxygen buffers (Fe_2O_3 + Fe_3O_4, Ni + NiO, Fe + Fe_3O_4, Fe + FeO, and Mo + MoO_2). Experimental results indicate that within a frequency range from 10~(-2) to 10~6 Hz, electrical conductivity is strongly dependent on signal frequency. Electrical conductivity shows an Arrhenius increase with temperature.