Abstract

The Deep Creek fault zone is made up of a series of NW-SE trending faults, and appears to be a “horse-tail” splay near the termination of the South Flank fault zone. Many authors have inferred dip-slip movement along the South Flank fault zone, but have not supported these claims using kinematic data and no previous kinematic data is available for the Deep Creek fault zone. The faults within the Deep Creek fault zone have steep, linear traces upon which both dip-slip and very nearly strike-slip (left-lateral oblique-slip, mainly) movement has occurred. The faults of the Deep Creek fault zone formed prior to deposition of the 30 m.y.-old Bishop Conglomerate, probably during the Paleocene. The slip data suggest a bimodal history of deformation with an early phase of near normal slip followed by a period of oblique to near strike-slip movement. The slip on these faults is probably due to localized stresses created by activity on the underlying Uinta Basin Boundary thrust. The termination of the South Flank fault and the occurrence of the Deep Creek fault zone may have formed as a possible accommodation zone between the western and eastern domes of the Uinta Mountain Range, a transfer zone between the Uinta Basin boundary thrust and the Asphalt Ridge fault, or a combination of these.