Geoelectric Upper Mantle Anomalies in the United States

Abstract

Geoelectric studies have shown that a pronounced high conductivity region exists in the upper mantle of the Southwestern United States. This anomaly is well correlated with other geophysical anomalies. Tne electrical measurements can be interpreted togive upper mantle temperatures very close to the melting point. Preliminary measurements near the California ocean-continent boundary indicate even higher conductivities exist in the mantle under the ocean.