Lake Mountain 7.5 Geologic Map (MP 18-2dm)

By: Bart J. Kowallis, John E. Hunt, Douglas A. Sprinkel, Skyler B. May, Todd D. Bradfield, and Kent D. Brown

The Lake Mountain quadrangle is along the south flank of the eastern Uinta Mountains located about three miles north of the town of Tridell, Uintah County, Utah. The area is popular for outdoor recreation, including fishing, hunting, four-wheeling, snowmobiling, hiking, and camping, mostly in Ashley National Forest in the northern part of the quadrangle. Most of the remaining part of the quadrangle includes farms, ranches, and the Uintah and Ouray Reservation.

Two important landmarks within the quadrangle are Dry Fork Canyon, which cuts across the northeast corner of the map area and contains glacial deposits of Smiths Fork age, and Lake Mountain, the quadrangle’s namesake, located southwest of Dry Fork Canyon. The combined geology of the quadrangle makes for a majestic landscape that begins with low-lying hogbacks and broad valleys in the south and transitions to deep glacier-influenced canyons and broad mountain slopes in the north.

Geology of the Lake Mountain quadrangle a wide range of bedrock formations that are generally tilted southward and complexly faulted by the northwest extent of the Deep Creek fault zone. The oldest formation is the middle Neoproterozoic Red Pine Shale overlain by Paleozoic strata (Mississippian Madison Limestone through the Permian Park City Formations). The southern half of the map area is characterized by several sets of hogbacks and flatirons that consist of Mesozoic bedrock units separated by broad piedmont surfaces or stream valleys. The youngest bedrock unit mapped is the Oligocene Bishop Conglomerate, which is exposed throughout the northern half of the map area.

The Lake Mountain quadrangle has a variety of unconsolidated surficial deposits of Quaternary age, dominated by landslide and slump deposits. Large landslides are located along the flanks of Lake Mountain and Mosby Mountain. Other unconsolidated deposits include colluvium, stream alluvium, three levels of alluvium, three levels of large piedmont deposits, and glacial till and outwash.

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Other Information:
Published: 2019
Pages: 13
Plates: 2
Scale: 1:24,000
Location: Utah
Media Type: Paper Map