Stratigraphic and Facies Relationships of Upper Part of Green River Formation and Lower Part of Uinta Formation in Duchesne, Uintah, and Wasatch Counties, Utah

Abstract

The Parachute Creek member of the Green River formation is an approximately time-equivalent zone across the Uinta Basin of Utah, as shown by the correlation of extensive thin tuff beds within the member. The top of the overlying Evacuation Creek member is regarded as the base of the Uinta formation. This formation boundary rises stratigraphically toward the center of the basin, as also shown by the correlation of tuff beds. Much of the lower part of the fluviatile beds of the Uinta formation as exposed along the Colorado-Utah line grades westward into beds that are in considerable part of lacustrine, playa, and mud-flat origin in an area of which Indian Canyon is the center. These beds, formerly considered a saline facies of the Green River formation, are here included as part of the Uinta formation.