Soft sediment deformation in Confusion Gulch
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Date
1967
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Publisher
The Ohio State University
Abstract
Confusion Gulch is located in Sanpete County, Utah, near the town of Ephraim, on the east face of the Gunnison Plateau. The rocks exposed in this area range in age from Jurassic to Eocene, and are represented by the Twist Gulch, Indianola, North Horn, and Flagstaff formations. The rocks of these formations represent lake, flood plain, and marine deposits. The structures present in Confusion Gulch suggest that the rocks making up the North Horn formation were deformed before they were completely lithified. Soft sediment is indicated by the formation of tight folds in sandstone that is now brittle, cracked pebbles in a conglomerate whose matrix is undisturbed, and split pebbles that have been bonded by sand matrix. Soft sediment deformation is responsible for the formation of the tight "S" fold on the front of the Gunnison Plateau, and for its overturned fold in the center section of Confusion Gulch.