Oil-impregnated sandstones of Raven Ridge, Vernal, Utah

The area of this report is in the northeastern part of the Uinta Basin of northeastern Utah and northwestern Colorado. The area covers approximately 52 square miles of what is regionally called Raven Ridge. Raven Ridge, a series of hogback ridges, trends northwest-southeast, and includes three Eocene formations, which dip to the west. They are, from oldest to youngest, the Wasatch Formation, the Green River Formation, and the Uinta Formation. Most of the oil-impregnated sandstones along Raven Ridge occur in the Green River Formation, therefore member terminology introduced by other workers for the Green River was extended through the area of study. Each deposit of tar sand is discussed with respect to the member in which it occurs. Field observations of the degree of saturation indicate whether these deposits may be economical in the future. Physical characteristics, such as thickness, dip, and extent help determine what mining methods might be applied. Because of the relatively steep dipping zones of saturation on Raven Ridge, in situ of these deposits appears to be the best method. In situ also presents fewer problems of pollution.