FTIR SPECTROSCOPY AND REFLECTANCE OF MODERN CHARCOALS AND FUNGAL DECAYED WOODS - IMPLICATIONS FOR STUDIES OF INERTINITE IN COALS

The chemical and physical characteristics of laboratory produced charc oals, natural charcoals, fungal decayed woods and inertinite from a va riety of Western Canadian coals have been investigated using FTIR and standard petrologic techniques. Our studies confirm and extend earlier work in showing that almost all inertinite macerals can be attributed to wildfire in peat swamps, and that variation in the petrological ch aracteristics of inertinite are a product of temperature, duration of heating and the nature of the initial plant material. The relationship s between reflectance and temperature, as well as heating duration of charcoal formation are established as a reference for the examination of inertinite and the probable temperature of inertinite precursor (fo ssil charcoal) formation in paleo-wildfire. Fungi do not directly cont ribute to the formation of charcoal and inertinite apart from the fung al bodies themselves (funginite: sclerotia and hyphae) and perhaps by increasing the extent of shrinkage and cracking (increasing surface ar ea) of the plant materials and thus susceptibility to charring. Eviden ce of fungal activity progressively decreases with increasing degree o f charing in response to duration of heating or increased charing temp erature. The reflectance values and FTIR spectral characteristics of i nertinites in Western Canadian coal suggest that most inertinite forme d by wildfires at temperatures over 400 degrees C. The great abundance of semifusinite in Western Canadian coal may reflect frequent but sho rt duration wildfires in precursor peat swamps. (C) 1998 Elsevier Scie nce B.V. All rights reserved.