| Description |
The P. R. Spring tar sand deposit is located in southeastern Uintah and northeastern Grand counties, Utah (Townships 11-17 South, Ranges 21-25 East ). The area lies in the southeastern corner of the Uinta Basin, adjacent to the Utah-Colorado State line. The regional dip in the area is gentle, generally 1-2° to the northwest. In the northeastern part of the area, the dip steepens to about 3° and is more westerly, reflecting the proximity of the north-south trending Douglas Creek Arch. Map VI, Structure Map-Top of the Douglas Creek, indicates the lack of major surface structure in the area. The main feature is the Hill Creek anticline which transects the southwestern part of the area from northwest to southeast. Faulting i s minor, with the few faults present striking westerly and having small displacements. Map VII, Surface Geology and Overburden Thicknesses, shows the contacts of the three formations at the surface of the area. In ascending order, the stratigraphic units are: the Wasatch Formation, the Douglas Creek Member of the Green River Formation, and the Parachute Creek Member of the same formation. The Wasatch Formation is exposed along the Roan Cliffs to the south. It also appears in the deeper canyons of the northerly running major streams which cut through the Douglas Creek Member. The Douglas Creek Member has the major surface exposure whereas the overlying Parachute Creek Member is confined to a broad arc which swings around from the southwest through the north to the northeast. The Parachute Creek is intricately dissected and has left behind a number of remnants (outliers) in its northerly retreat. The tar sands or oil-impregnated sandstones (OISS) are the major resource in the area. They are found in the lower part of the Parachute Creek and the upper part of the Douglas Creek. Locally, there is minor interbedded oil shale. The foregoing geologic description is abstracted from the following authors, and it is recommended that their publications be consulted for greater detail: Cashion (1967), Byrd (1970), Gwynn (1971), Peterson and Ritzma (1974), and Peterson (1975). |
