The Permian-Triassic Stratigraphy of the Northwest Paradox Basin Area, Emery, Garfield, and Wayne Counties, Utah

Abstract

The Upper Permian and Lower Triassic rocks in the northwestern Paradox basin are closely related even though they are separated by a significant unconformity. Careful analysis of surface and subsurface data provides a framework to relate underlying units to deposition of suprajacent units. The Black Dragon Member of the Triassic Moenkopi Formation infilled the topography on the underlying Permian units. The thickness of the Black Dragon Member is inversely related to the thickness of the underlying White Rim Sandstone. The upper portion of the Black Dragon Member was deposited primarily in coastal marine environments with a very low westward depositional slope. An oolite-bearing carbonate shelf present during subsequent Sinbad Member deposition was also controlled, in part, by thickness distribution of the Permian White Rim Sandstone. The Torrey Member was deposited on the Sinbad Member in a fine-grained, elastic-dominated, low energy, very flat coastal environment. The Moody Canyon Member (uppermost Moenkopi) was deposited in a subaqueous environment, probably marine. The Emery uplift, a pre-White rim tectonic element, did not affect deposition of the White Rim, Kaibab or Moenkopi strata. The San Rafael Swell is a Laramide tectonic feature that is offset from and unrelated to the Emery uplift or deposition of the Permian and Triassic units.