Paleocurrent measurements of 175 linear asymmetrical ripple marks were taken at seven sections of the Moenkopi Formation in northeastern Utah. Five of

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the sections are on the south flank of the Uinta Mountains, where 123 measurements were taken. A total of 52 measurements was made at two sections on the north flank of the Uinta Mountains. Linear asymmetrical ripple marks were used exclusively because of their abundance at each section.

Analysis of the paleocurrent data indicates three major current directions during deposition of the Moenkopi: northwest, southeast, and southwest. These are interpreted as representing wave-drift, rip, and longshore currents moving on and along a generally northeast-southwest-trending shoreline that bordered a shallow marine shelf during the Early Triassic.

When the paleocurrent data of the north and south flanks of the Uinta Mountains are considered separately, the average northeast-southwest-trending shoreline of the south flank is interpreted to shift to a north-south trend on the north flank. This gradual shifting of the shoreline trend probably continued into Wyoming where Picard and High found a northwest-southeast trend in the Moenkopi equivalent (Red Peak Formation) in west-central Wyoming. The interpreted shoreline trend parallels the isopach trend of the Moenkopi Formation in northeastern Utah.

Interpretation of shoreline trends leads to the evaluation of the depositional environments, current directions, and paleogeography during the time of deposition. Economic interest in shoreline trend interpretation is high and will continue to be so in the future because of oil and gas exploration efforts.

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