NEW GEOLOGIC MAPPING OF THE PROVO 30' X 60' QUADRANGLE, SALT LAKE, UTAH, AND WASATCH COUNTIES, UTAH

The Utah Geological Survey recently completed a new geologic map and GIS dataset of the Provo 30' x 60' quadrangle. This interim geologic map was compiled from detailed new mapping of key 7.5' quadrangles, revised previously published 7.5' quadrangles, and new 1:24,000 to 1:50,000-scale reconnaissance geologic mapping, producing complete coverage at a scale of 1:62,500. This new map fills a gap in Utah's intermediate-scale geologic map coverage and is available as a paper map or GIS files.

The Provo 30' x 60' quadrangle covers part of the populous Wasatch Front and Utah Valley, which have many different geologic hazard concerns, and the adjacent Wasatch Range, with competing recreational, forest, watershed, and geologic resource issues. Precambrian to Cretaceous sedimentary strata were deformed by Late Cretaceous to early Tertiary contractional folding and faulting of the Sevier orogeny, middle Tertiary regional extensional collapse or relaxation that was accompanied by igneous activity, and late Tertiary to Holocene basin-and-range extensional faulting. Much of the eastern part of the quadrangle is covered by Tertiary strata that were deposited after the Sevier orogeny and before and during middle Tertiary extension. The most prominent feature of the basin-and-range extensional faulting is the Provo segment of the Wasatch fault zone, which separates Utah Valley from the Wasatch Range. Utah Valley is filled with up to 4500 meters of basin fill that is mostly mantled by late Pleistocene Lake Bonneville deposits. Late Pleistocene glacial deposits are present at higher elevations in the Wasatch Range.