QUALITY AND PETROGRAPHIC CHARACTERISTICS OF PALEOCENE COALS FROM THE HANNA BASIN, WYOMING

Coal beds from the Ferris and Hanna Formations, in the Hanna basin, so uth-central Wyoming, exhibit distinct differences in ash yield, sulfur content, and petrographic and palynologic constituents. These differe nces are interpreted to be controlled by tectonic changes of the Hanna basin and adjoining uplifts during evolutionary development, which, i n turn, controlled mire chemistry and sedimentation. These conditions created two very different settings under which the peats developed du ring deposition of the Ferris and the Hanna Formations. In addition, t here appears to be a geographic (latitudinal) and/or climatic control on the coal characteristics manifested by major differences of Paleoce ne coals in the Hanna basin compared to those in the Raton basin in Co lorado and New Mexico and the Powder River basin in Wyoming.