Journal
EUROPEAN JOURNAL OF MINERALOGY
Volume 21, Issue 3, Pages 615-622Publisher
E SCHWEIZERBARTSCHE VERLAGSBUCHHANDLUNG
DOI: 10.1127/0935-1221/2009/0021-1933
Keywords
wadsleyite; hydrous minerals; high pressure; electrical conductivity; complex impedance spectroscopy; transition zone
Categories
Ask authors/readers for more resources
In situ complex impedance spectroscopy of H2O-bearing wadsleyite was performed in a multianvil apparatus at 14 GPa at temperatures up to 950 degrees C in order to determine electrical conductivity. With increasing H2O content in wadsleyite the electrical conductivity increases at a rate higher than observed in previous studies. The activation enthalpy in the temperature range studied where proton conduction dominates is low (0.66 eV) suggesting an inevitable crossover to small polaron conduction at moderately higher temperatures, depending on H2O concentration. Although the solubility of H2O in wadsleyite is significant for a silicate mineral (>3 wt%), the presence of more than trace dissolved H2O in wadsleyite is likely to result in a conductivity too high compared to recent estimates of transition-zone conductivity. The use of complex impedance spectroscopy shows that the frequency dependence of electrical properties is very different in the case of H2O-bearing silicate phases. At frequencies below 1000 Hz complex impedance spectra contain strong features which likely result from the sample-electrode interface such that including the low-frequency data would lead to artificially low conductivities.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available