Comparison of continental and oceanic mantle electrical conductivity: Is the Archean lithosphere dry?

摘要: [1] Electrical conductivity profiles derived from magnetotelluric and geomagnetic sounding methods provide a means of constraining upper mantle properties that is complementary to seismic studies. We analyze for an Archean craton oceanic setting, in conjunction with independent constraints on geotherms, estimate the water content these very different geologic environments. Results this analysis indicate lithosphere contains less than depth range between ∼150 ∼250 km. Below km continental environments show similar conductivities, suggesting does not vary significantly 410-km discontinuity. These observations may be stabilized against convective instabilities partly because it has high viscosity associated dry composition.