Abstract

Paleomagnetic studies on the upper half of the Moenkopi Formation have identified three reversed and three normal polarity zones; this brings the total number of polarity zones observed in this formation to ten. The variable thickness and presumed duration of these polarity zones when combined with smaller variations internal to individual polarity zones suggest that this reversal sequence should be very useful as a regional correlation tool.

Several zones of anomalous magnetization have been recognized within the formation. These anomalous zones constitute less than 5 percent of the total sample population but are very important, because they may assist in the recognition of individual polarity zones.

The pole position derived from this study is at 103° E., 55° N. (dp 1.6°, dm 3.2°) and, due to the large number of samples and the length of time represented, probably represents an excellent average for the Lower Triassic of North America.

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