Magnetotellurics and geomagnetic deep sounding
Article first published online: 12 APR 2012
©1971. American Geophysical Union. All Rights Reserved.
Eos, Transactions American Geophysical Union
Volume 52, Issue 5, pages IUGG 213–IUGG 216, May 1971
How to Cite
1971), Magnetotellurics and geomagnetic deep sounding, Eos Trans. AGU, 52(5), IUGG 213–IUGG 216, doi:10.1029/EO052i005pIU213.(
- Issue published online: 12 APR 2012
- Article first published online: 12 APR 2012
The correlation of enhanced electrical conductivities in the upper mantle with high surface heat flow and reduced seismic velocities has been demonstrated in such tectonic areas as the western United States and Iceland. Therefore, arguments that magnetotelluric and geomagnetic variation anomalies in these areas are an indication of enhanced temperature at depth become very persuasive.
It is quite possible that the interpretation of geomagnetic variation anomalies along the Wasatch front, the Rocky Mountain front, and the Rio Grande rift will ultimately be of great importance in understanding the fundamental tectonic processes beneath the North American cordillera. To the south of the Colorado plateau, Schmucker  explains the anomaly by a deep zone of high conductivity whose axis strikes parallel to the Rocky Mountain front. The depth to the top of this zone is approximately 160 km under the Basin and Range province, 100 km under the Rio Grande rift belt; and perhaps 250 km beneath the Texas foreland. The development of a low-cost portable variometer by Gough and Reitzel  permitted dense coverage of the region north of Schmucker's profile by a large number of stations simultaneously. Interpretation of these data revealed two northerly trending ridges of high conductivity in the mantle, one beneath the southern Rockies (east of the Colorado plateau), the other beneath the Wasatch front (west of the Colorado plateau).