The electrical conductivity of dry sintered olivine aggregates with various contents of magnetite (0, 3, 5, 7, 10, 20, and 100 vol. %) was measured at temperatures of 873-1273 K and a pressure of 2.0 GPa within a frequency range of 0.1-10(6) Hz. The changes of the electrical conductivity of the samples with temperature followed an Arrhenius relation. The electrical conductivity of the sintered olivine aggregates increased as the magnetite-bearing content increased, and the activation enthalpy decreased, accordingly. When the content of interconnected magnetite was higher than the percolation threshold (similar to 5 vol. %), the electrical conductivity of the samples was markedly enhanced. As the pressure increased from 1.0 to 3.0 GPa, the electrical conductivity of the magnetite-free olivine aggregates decreased, whereas the electrical conductivity of the 5 vol. % magnetite-bearing sample increased. Furthermore, the activation energy and activation volume of the 5 vol. % magnetite-bearing sintered olivine aggregates at atmospheric pressure were calculated to be 0.16 +/- 0.04 eV and -1.50 +/- 0.04 cm(3)/mole respectively. Due to the high value of percolation threshold (similar to 5 vol. %) in the magnetite impurity sample, our present results suggest that regional high conductivity anomalies in the deep Earth's interior cannot be explained by the presence of the interconnected magnetite-bearing olivine aggregates. Publication name | MINERALS, 9 (1):10.3390/min9010044 JAN 2019 | Author(s) | Dai, Lidong; Hu, Haiying; Sun, Wenqing; Li, Heping; Liu, Changcai; Wang, Mengqi | Corresponding author(s) | DAI Lidong; HU Haiying dailidong@vip.gyig.ac.cn; huhaiying@vip.gyig.ac.cn Chinese Acad Sci, Inst Geochem, Key Lab High Temp & High Pressure Study Earths In, Guiyang 550002, Guizhou, Peoples R China. | View here for the details
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