NEW GEOLOGIC MAPS OF UTAH'S URBAN FRINGE

The Utah Geological Survey recently published new geologic maps of the Traverse Mountains, an anomalous, east-west-trending mountain range that separates the urban centers of Salt Lake and Utah Valleys. The east part of the range occupies a major segment boundary on the Wasatch fault, the most recent manifestation of a long-lived, east-west-trending zone of crustal weakness that was active during the Late Cretaceous to early Tertiary Sevier orogeny as a sidewall ramp of the Charleston thrust fault, and, following the gravitational collapse of the orogenic belt, as the Deer Creek detachment fault. The west end of the range preserves the distal flank of the late Eocene Bingham volcanic center, and throughout the range, late Eocene to early Oligocene volcanic rocks unconformably overlie paleotopography eroded into broad, northwest-trending folds in Paleozoic strata. The Traverse Mountains are ringed with shoreline features and deposits of Lake Bonneville, which are important sand and gravel resources for adjacent metropolitan areas. The range also holds aggregate and clay resources needed to support local construction, and is host to a variety of geologic hazards, including large landslides, debris flows, and active earthquake faults. The Traverse Mountains are at the forefront of explosive suburban growth and are fast becoming a refuge for those seeking to escape the hassles of urban life. New geologic maps of this region – the Jordan Narrows, Lehi, and Tickville Spring 7.5' quadrangles, funded in part through the USGS Statemap Program – are an important tool used to address geologic hazard and geologic resource concerns associated with rapid development. The maps will also form the foundation for educational displays and a guidebook to the geology of the region.