GEOLOGIC MAP OF OGDEN VALLEY, UTAH AND SURROUNDING AREAS

Three recent geologic maps of the North Ogden, Huntsville, and Browns Hole 7.5’ quadrangles provide a detailed foundation of geology for Ogden Valley and surrounding areas. Together these maps cover most of Ogden Valley, a rapidly developing and scenic back-valley of the urbanized Wasatch Front, east of Ogden, Utah. The maps also cover the rugged Wasatch Range that bounds Ogden Valley, home to critical watersheds, recreation, and wildlife habitat, as well as part of the Great Salt Lake basin near the city of North Ogden. New mapping builds on previous 1:24,000-scale U.S. Geological Survey maps and 1:62,500-scale Utah Geological Survey maps, but adds necessary detail to bedrock, structures, and Quaternary deposits. These maps provide foundations for geologic hazard, geotechnical, resource, environmental, and hydrologic studies that support safe and sustainable urban growth.

The bedrock geology includes Tertiary tuffaceous deposits, Paleozoic and Neoproterozoic sedimentary rocks, and Paleoproterozoic to Mesoproterozoic metamorphic rocks that are cut and folded by the Willard and Ogden thrust faults of the Cretaceous–Eocene Sevier orogeny. The bedrock in the Wasatch Range is bounded by the north part of the Weber segment and southern part of the Brigham City segment of the Wasatch fault zone, a major basin-bounding active fault zone with Holocene activity. The Ogden Valley North Fork fault, Ogden Valley Southwestern and Northeastern Margin faults are Quaternary active and bound the east and west sides of Ogden Valley. A series of large earthquake-induced lateral spread and flow failures caused by prehistoric earthquake ground shaking cover much of the west side of the Great Salt Lake valley floor near the town of North Ogden. Landslides are common in the Neoproterozoic sedimentary rocks and Tertiary tuffaceous deposits. Quaternary glacial deposits mapped below Willard Peak and Ben Lomond are likely the result of Pinedale and Bull Lake glaciations. Quaternary Lake Bonneville deposits and shorelines dominate the valley deposits along the Wasatch Range and in the lower-elevation parts of Ogden Valley.