HR: 0800h
AN: MR11A-0928    [Abstracts]
TI: Electrical Conductivity Beneath Slave Craton (Canada) From Laboratory Experiments
AU: * Bagdassarov, N S
EM: nickbagd@geophysik.uni-frankfurt.de
AF: Institut fuer Meteorologie und Geophysik, J. W. Goethe Universitaet Frankfurt, Feldbergstrasse 47, Frankfurt am Main, 60323 Germany
AU: Eichert, S
AF: Institut fuer Meteorologie und Geophysik, J. W. Goethe Universitaet Frankfurt, Feldbergstrasse 47, Frankfurt am Main, 60323 Germany
AU: Kopylova, M
EM: mkopylova@eos.ubc.ca
AF: Geological Sciences Division, Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, V6T1Z4 Canada
AB: The electrical conductivity beneath Slave craton in North Canada has been characterized on the base of the laboratory measurements of peridotite sample resistance, which have been studied mineralogically in previous works (Kopylova & Russel, 2000; Kopylova & Garo, 2004). The chemical composition of peridotites representing differing depths beneath the Slave craton has been chosen as follows, for the depth from 36 to 100 km spinel peridotite (40-16), from 100 to 140 km low-T spinel-garnet perodotite (41-4), from 140 to 160 km low-T garnet peridotite (8-7), from 160- to 260 km high-T garnet peridotite (40-9). The conductivity of samples were determined in piston-cylinder apparatus at 1 and 2 GPa and in the temperature interval from 600 to 1150$\deg$C. The electrical measurements were conducted in the frequency range from 100 kHz to 10 mHz in a measuring cell having a coaxial capacitor geometry with a geometric factor c. 5-6 cm. The temperature dependence of electrical conductivity follows the Arrhenius dependence with the activation energy varying from 1.94 (sample 40-9) to 1.77 eV (sample 8-7). The pressure increase from 1 GPa to 2 GPa results ina a small increase of the activation energy for $\sim$0.1 eV. Using the temperature profile beneath Slave craton based on thermobarometry of mantle xenolithes from Jericho pipe (Kopylova et al. 1999) the depth profile of the electrical conductivity has been constructed. The magneto-telluric response of these model has been compared with the field MT observations (Jones et al., 2003) with a satisfactory agreement for phase and apparent resistivity in the frequency range $10^{-2}$ to $10^2$ Hz.
DE: 8124 Earth's interior--composition and state (old 8105)
DE: 5109 Magnetic and electrical properties
DE: 5460 Physical properties of materials
DE: 3914 Electrical properties
DE: 3924 High-pressure behavior
SC: Mineral and Rock Physics [MR]
MN: 2004 AGU Fall Meeting