Petrography and Chemistry of the Miocene lacustrine coals in the Neogene Domaniç basin, Western Turkey: coal depositional environment


Authors: Çelyk Y

Published in: Bulletin of Geosciences, volume 74, issue 2; pages: 139 - 144;

Keywords: Coal deposition, bituminous coal, coal petrography, maceral, microlithotype, lacustrine environment, limnic, neogene, western Turkey,

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Domaniç basin is one of the most important coal basins of western Anatolia. Coal horizons in this basin consist of coal seams. Lower and upper lignite seams are considerably thinner and have no economic value. The development of lower and upper seams provide important clues for sedimentation conditions.
The main coal seams of the Neogene Domaniç basin are of Miocene age and have thickness of 3 to 11 meters. The investigated coals are composed of 10-19.2 wt. % moisture contents, 28.6-58 wt. % ash, 25.64-35.63 wt. % volatile matter, 16.36-37.09 wt. % fixed carbon, 0.55-3.39 wt. % total sulfur content and 2015-4231 kcal/kg calorific values.
The lithotype of the coal seam includes durain and less vitrain as dominant. The most abundant maceral group of coals is huminite and macerals is gelinite. The amount of the liptinite maceral group seems to be considerably greater than that of the inertinite group, the liptinite macerals consist of sporinit and lacustrine alginites. The most dominant microlithotypes of coals are humite, carbargilite, clarites and duroclarites.
Tha values of ulminite reflectance (Rmax, in oil) are between 0.38 % and 0.50 % reflectance values and chemical analyses indicate that coals can be classified as subbituminous in the ASTM classification.
The interpretation of depositional environment of the main coal seams and the other investigations as well as sedimentological properties seem to indicate that coals deposited within a limnic environment, mainly in a reed-moor of the limno-telmatic and telmatic zone. Peat accumulation began subaquatically and deposition under fresh-water conditions continued.