Variation in the petrological, mineralogical and palynological characteristics of some Upper Pennsylvanian coals from the northern Appalachian Basin

Middle and Upper Pennsylvanian-age sediments of the Appalachian Basin have been proposed to represent periods during which significant changes in climate occurred. The Allegheny Group and Monongahela Group formed during wet climatic conditions, whereas the Conemaugh Group spans an extremely dry period. In this study the palynological content and the petrographic and mineralogic nature of the coals were examined for possible correlation with climate.;Twenty-nine column, 5 subsection-channel and 14 whole-seam channel samples were collected from western Pennsylvania, northwestern Maryland and northern West Virginia, representing the Upper Allegheny, the Lower and Upper Conemaugh and the lowermost Monongahela Groups. Most samples were columns from the Lower Conemaugh Group taken from western Pennsylvania.;The coals of the Conemaugh Group were found to have the following characteristics: (1) They are totally lacking in Lycospora (spores of arborescent Lepidodendrales). (2) They are thinner than the coals of the lower (Upper Allegheny and lowermost Conemaugh) and higher (Upper Conemaugh and Monongahela) stratigraphic intervals. (3) They have low vitrain and clarain contents, with duller subsections than the stratigraphically lower and higher coals. (4) They have lower vitrinite plus liptinite content than the coals of the lower and higher stratigraphic intervals. (5) They contain mineral and maceral associations rich in inertinite macerals, notably semifusinite, inertodetrinite, and resinosclerotinite. (6) They have higher ;These coal properties are interpreted to reflect the cumulative effects of paleoclimate, tectonism that changed hydrologic base level, plant input and rate of subsidence. By far the most important factor influencing the character of peat deposited during the Upper Pennsylvanian was climate.