Abstract

The Sage Valley-Elk Valley area straddles the Idaho-Wyoming border in the central part of the Overthrust Belt. Approximately 5,400 meters of strata are exposed, including the Pennsylvanian Wells Formation through the Tertiary Salt Lake Formation. An intertonguing relationship of members within the Phosphoria Formation, the Woodside Formation with the Dinwoody Formation, and the Ankareh Formation with the Thayes Formation is recognized. Mapping of that facies relationship within the Cretaceous Ganett Group in the Sage Valley-Elk Valley area shows rocks previously mapped as Ephriam Conglomerate are now known to include Ephriam Conglomerate, Peterson Limestone, Bechler Conglomerate, and Draney Limestone. Rocks previously mapped as the Cretaceous Wayan Formation are now mapped as Smoot Formation and Tygee Member of the Bear River Formation.

Seven hydrocarbon test wells have been drilled in or near the area and significant hydrocarbon shows have been reported from several of these wells. Several surface shows of hydrocarbons are also reported, therefore the potential for economic hydrocarbon accumulations in the Sage Valley-Elk Valley area is good. Phosphatic rocks from the Phosphoria Formation and various construction materials from the Twin Creek Limestone and Stump Sandstone may be of economic importance.