Abstract

The stratigraphy, sedimentation, conodont zonation, and source-rock potential of the Upper Devonian and Lower Mississippian Pilot Shale and the Mississippian Chainman Shale are interpreted in relation to a composite measured section of each formation in the Confusion Range, Utah. The Pilot and Chainman Shales, which were deposited in the eastern part of the Antler foreland basin, contain some probable petroleum source beds in this area. Organic-carbon values in weight percent are given for 48 sampples from the Pilot and 35 samples from the Chainman. Conodont collections from these formations have CAI (color-alteration index) values of 1, 1.5, and 2, but most have a CAI value of 1.5, which indicates submature to mature thermal maturation of organic matter. The Pilot contains large, well-preserved conodont faunas that support the worldwide standard Upper Devonian conodont zonation. The Chainman contains sparse conodont faunas that provide the basis for a preliminary zonation of the Chesterian.