Electrical properties of natural clay permafrost

• Published in: Canadian Journal of Earth Sciences
• Main Author: Olhoeft, Gary R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1977
• Subjects: Ice; permafrost
• Online Access: http://dx.doi.org/10.1139/e77-002; http://www.nrcresearchpress.com/doi/pdf/10.1139/e77-002

The resistivity, dielectric constant, and loss tangent of natural clay permafrost samples that have never been thawed have been measured as functions of temperature, applied uniaxial confining load, and applied electric field strength. DC resistivities are on the order of 10 5 ohm-m at −10 °C, with the complex resistivity becoming strongly frequency dependent within and above the range of 10 to 10 3 Hz (resistivity decreasing with increasing frequency). Below 10 3 Hz, the electrical properties are slightly dependent upon applied electric held, and below 10 5 Hz, the electrical properties are very strongly dependent upon applied uniaxial confining load. Several different mechanisms are responsible for the observed properties, including ionic conduction, a colloidal response that is similar to a Maxwell-Wagner type of effect, the relaxation of Bjerrum defects in ice, the relaxation of the unfrozen water molecules, and a possible relaxation of organic molecules in the unfrozen water sheath surrounding clay particles.