Abstract

The Black Box Dolomite of the San Rafael Swell area is a new name for the distinctive Permian “Kaibab” carbonate unit deposited on the Emery high. The Black Box Dolomite is the lateral equivalent of the upper cherty limestone of the Fossil Mountain Formation of the Kaibab Group. On the west and the north sides of the Emery high the Black Box Dolomite also contains cherty dolomite equivalent with the Lower Plympton Formation. The Black Box Dolomite is known to rest unconformably upon the Deseret, Cedar Mesa, and White Rim Formations.

The Upper Permian sequences in Utah are subdivided into six paleo-geographic areas based upon lithostratigraphic continuity. The sequences are the Phosphoria slope and basin, the Kaibab platform with sebkas, the Park City shelf, the Black Box Dolomite on the Emery high, and the White Rim littoral zone.

Upper Permian rocks rest conformably upon Leonardian rocks of the Pequop and Arcturus Formations in northwest Utah; unconformably upon the Wolfcampian Queantoweap, Organ Rock and Cedar Mesa in southern Utah, and the Weber Sandstone in northeastern Utah. In southeastern Utah the Triassic Moenkopi Formation rests unconformably upon the Wolfcampian Cutler Formation and there are no rocks equivalent to the Kaibab, Park City, and Phosphoria Groups adjacent to the Uncompahgre Uplift.