Pennsylvanian coals of central and eastern United States
Published:January 01, 1991
Geologic conditions during the Pennsylvanian created events necessary for coal-forming that are relatively rare in geologic history. This mix of conditions involved (1) tectonics accompanied by sedimentation; (2) depositional environments that favored poorly drained, clear-water, acidic swamps; (3) climates that encouraged peat formation and preservation; (4) plant evolution that produced sufficient biomass to keep pace with a changing base level; and (5) repeated cycles of marine and nonmarine sedimentation, alternating between detrital influx and “starvation” in response to eustatic, tectonic, and sediment-supply changes. Factors important in determining the quality and thickness of coal beds are the relative rates of...
Figures & Tables
Economic Geology, U.S.
This volume includes sections on Mineral Deposits (7 chapters on metals and 4 on industrial minerals); Oil and Gas (3 chapters on principles and 12 synthesizing major oil and gas basins); and Coal (3 chapters on principles and 5 synthesizing major coal provinces, including Alaska). Six large plates summarize distribution resources of all resources discussed in the text, two more plates compare cross-sections of major oil and gas basins at a common horizontal and vertical scale, and another shows a major reconstruction of a Pennsylvanian coal swamp.