NEW 1:24,000-SCALE GEOLOGIC MAPS OF UTAH'S CAPITOL CITY AND SURROUNDING AREAS: FROM BEDROCK TO BONNEVILLE AND RUGGED WILDERNESS TO UTAH'S OLDEST URBAN LANDSCAPE

New 1:24,000-scale geologic maps of the Salt Lake City North and Fort Douglas quadrangles provide an updated geologic framework for downtown Salt Lake City and surrounding areas. These maps encompass parts of Salt Lake Valley, the Salt Lake City foothills, and the rugged Wasatch Range. The maps cover critical watersheds, recreation areas, and wildlife habitats at the fringe of the Wasatch Front urban corridor. The maps also cover areas of major infrastructure, including the Salt Lake City International Airport, interstates, railroads, refineries, the State Capitol building, and major economic development centers like inland ports, downtown Salt Lake City, and the University of Utah and its medical complex and research facilities. These maps provide foundations for geologic hazard, geotechnical, resource, environmental, and hydrologic studies, all of which support safe and sustainable growth in the state’s capital.

These new maps show: 1) improved locations, ages, and structural connections between the north end of the Quaternary-active Salt Lake City Segment and the south end of the Weber segment of the Wasatch fault zone, 2) a westward migration path of the Jordan River delta since the retreat of Lake Bonneville, 3) updated Tertiary stratigraphy, geochronology, and structural history of the Rudy’s Flat fault, 4) updated Paleozoic bedrock stratigraphy, nomenclature, and member identification and delineation of Cambrian rocks, Permian Park City Formation, and Jurassic Twin Creek Formation, 5) updated bedrock structure, new faults and folds, and new cross sections, 6) updated nomenclature, identification, and delineation of mass-movement deposits, including rock slides, lateral spread deposits, and historically active landslides that impact infrastructure, 7) updated nomenclature, identification, and delineation of Pleistocene Lake Bonneville and associated deposits, and 8) identification and delineation of Pleistocene glacial deposits in upper elevation terrain.