The Miocene lavas of the southern part of the Columbia Plateaus are exposed by major northerly trending faults. In such terrane, normally and reversely magnetized zones of lavas could be expected to provide a method for broad stratigraphic correlation. As a result of a large-scale paleomagnetic survey, major sections in the region have been observed to possess only a single polarity.

During the summer of 1962, however, some fine and apparently rapid systematic variations of the direction of the ancient ambient magnetic field were observed within zones of both normally and reversely magnetized lavas. These systematic variations are likely to yield an accurate tool for correlation across the faults. Should oil-bearing sediments be sought beneath the lavas, the throws of the faults will be of major importance, and paleomagnetism could thus assist significantly in exploration in this area.

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