Experimental study on the electrical conductivity of quartz andesite at high temperature and high pressure: evidence of grain boundary transport
Other literature type, Article
Hui, K. S.
Li, H. P.
Dai, L. D.
Hu, H. Y.
Jiang, J. J.
Sun, W. Q.
- Publisher: Copernicus Publications
(issn: 1869-9529, eissn: 1869-9529)
Petrology | Q | QE500-639.5 | Dynamic and structural geology | QE640-699 | Science | QE1-996.5 | Geology | Stratigraphy | QE420-499
In this study, the electrical conductivity of quartz andesite
was measured in situ under conditions of 0.5–2.0 GPa and 723–973 K using
a YJ-3000t multi-anvil press and a Solartron-1260 Impedance/Gain-Phase
Analyzer. Experimental results indicate that grain interior transport
controls the higher frequencies (10<sup>2</sup>–10<sup>6</sup> Hz), whereas the grain
boundary process dominates the lower frequencies (10<sup>−1</sup>–10<sup>2</sup> Hz).
For a given pressure and temperature range, the relationship between Log
σ and <i>T</i><sup>−1</sup> follows the Arrhenius relation. As temperature increased,
both the grain boundary and grain interior conductivities of quartz andesite
increased; however, with increasing pressure, both the grain boundary and
grain interior conductivities of the sample decreased. By the virtue of the
dependence of grain boundary conductivity on pressure, the activation
enthalpy and the activation volume were calculated to be 0.87–0.92 eV and
0.56 ± 0.52 cm<sup>3</sup> mol<sup>−1</sup>, respectively. The small polaron conduction
mechanism for grain interior process and the ion conduction mechanism for
grain boundary process are also discussed.