PALEOCURRENT ANALYSES OF THE TERTIARY COLTON AND CRAZY HOLLOW FORMATIONS, CENTRAL UTAH: IMPLICATIONS FOR TIMING OF THE WASATCH MONOCLINE

Paleocurrent analysis is an important tool for establishing the relationship between local sedimentation and regional tectonism. In central Utah, a dominant structural feature is the 90 km long Wasatch monocline. Units exposed along the limb of the monocline include the Tertiary Colton and Crazy Hollow Formations, which have been interpreted as mixed fluvio-lacustrine units deposited on the margins of Lakes Flagstaff and Uinta, respectively. The purpose of this research is to determine if sediment dispersal within Colton and Crazy Hollow sandstones was affected by topographic highs produced during uplift of the Wasatch monocline.

Previous work in the Colton Formation indicates that deposition occurred on a regional paleoslope to the NE. Detailed paleocurrent data from the Crazy Hollow Formation has not been published, but several workers have suggested that paleoflow during its deposition was also to the NE and E.

For this study, Colton paleocurrents were measured at 12 localities (253 measurements). Paleoflow was dominantly to the N and NW across the study area, with only minor local variability. The consistency of this pattern indicates that the Wasatch monocline was not a regional topographic high during Colton deposition. Crazy Hollow paleocurrents were measured at 16 localities (296 measurements). Paleoflow was to the N in the central portion of the study area, but to the S along the northern and southern edges of the study area and to the E and NE along the western edge of the study area. This variability within the Crazy Hollow Formation is interpreted to record either the complicated paleogeography of Lake Uinta or the development of more meandering dispersal systems, since uplift of the Wasatch monocline should have had a more uniform influence on paleoflow patterns throughout the study area.