Interim Geologic Map of the Summit Quadrangle, Iron County, Utah (OFR-775DM)

by Tyler R. Knudsen

Summary

The Summit 7.5' quadrangle is centered on the town of Summit, Iron County, in southwestern Utah and covers the precipitous Hurricane Cliffs along the northwestern margin of the Markagunt Plateau and part of southern Parowan Valley. Bedrock in the quadrangle consists of sedimentary and volcanic rocks ranging in age from Late Cretaceous to Early Pleistocene. The modern landscape is dominated by northeast-southwest-trending Basin and Range normal faults that form a series of horsts and grabens, the largest of which is the Parowan Valley. The Parowan fault and nearby intrabasin faults in Parowan Valley have locally displaced young Quaternary-age deposits, indicating that the faults should be considered hazardous. The Oligocene- and Miocene-age volcanic rocks in the quadrangle and Miocene-age regional-scale gravity-slide deposits are derived from the Marysvale volcanic field about 45 miles (72 km) to the north. Extensive Quaternary-age landslide complexes conceal much of the bedrock near Elliker Basin, Braffits Creek, and Summit Creek.

Other Information

• Published: 2026
• Pages: 19
• Plates: 2
• Scale: 1:24,000
• Location: Utah
• Media Type: Folded or rolled paper map and report

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