MORPHOLOGY, FORMATION AND PALAEO-ENVIRONMENTAL IMPLICATIONS OF NATURALLY FORMED CHAR PARTICLES IN COALS AND CARBONACEOUS MUDSTONES

Combustion char morphotypes are derived from pulverised fuel combustio n of coal. Microscopic examination of polished blocks of Carboniferous , Permian and Jurassic coals and carbonaceous mudstones has, however, also revealed the occurrence of particles with typical char morphology in these deposits. The particles are whiter than the associated humin ite/vitrinite and should be considered to belong to the inertinite mac eral group, but in both morphology and derivation they do not correspo nd to any of the established inertinite macerals. Thus, these morphoty pes are considered to represent naturally formed char. They are genera lly of the dense crassinetwork/ mixed network/mixed and inertoid char morphotypes. Low temperature combustion of coal, particularly in a muf fle furnace, yields similar char morphotypes, hinting that the natural ly formed chars were derived by low temperature burning of gelified or ganic matter. This may have been during surface/ground fires in peat m ires. Thus, despite their minor importance volumetrically, the natural ly formed chars may have palaeo-environmetal implications, particularl y if additional evidence is provided by pyroinertinite and/or pyrolyti c carbon. (C) 1998 Elsevier Science Ltd. All rights reserved.