COAL SYSTEMS–AN INTEGRATED APPROACH TO THE STUDY OF COAL GEOLOGY

Coal geology includes studies that range from modern analogues for peat formation, through the effects of burial, diagenesis, epigenesis, and coalification on these organic accumulations, to the preservation of coal in beds that may be mined and/or serve as sources and reservoirs for coalbed methane. In addition, the stratigraphy and sedimentology of coal-bearing strata are major elements of coal geology. Coal geology studies, however, commonly are fragmented into relatively restricted areas of interest. Integrated coal system models generally have not been developed as a scientific tool in order to understand and describe the formation and characteristics of coal deposits and their associated strata.

Coal system models would describe the geologic processes that impact carbon-rich sediments from their initial deposition as peat to the ultimate utilization of the coal resource; coal systems include accumulation, burial and preservation, and diagenetic to epigenetic coalification phases. Studies of the accumulation phase, including plant communities, geochemistry, hydrogeology, climatology, and sedimentology of recent and ancient mires, should be integrated with preservation phase studies of basin architecture and evolution, tectonics, eustacy, and sedimentation, as well as with studies of the diagenetic, epigenetic, and coalification processes that result in the final coal deposit and associated coalbed methane. The coal resource, which is described geologically by its rank (lignite to anthracite), thickness, aerial extent, geometry, petrology (maceral type), and chemistry, as well as by its potential to generate biogenic and thermogenic gases and liquids, is the product of many complex, interrelated processes. Utilization of an integrated coal systems approach in studies of coal geology should lead to an improved capability to characterize, assess, understand, and selectively develop the abundant coal resources of the world.