We have determined the maceral composition of coal cores from the Tyumen and Vasyugan Formations in the southeast of the West Siberian megabasin (Tomsk and Novosibirsk oblasts) using reflected light microscopy. We have identified the groups, classes, subclasses, types, and subtypes and have provided photographs of the most typical macerals and their percentages in some samples. There is a similar maceral composition of the studied coals from the Tyumen and Vasyugan formations. The revealed variations in the maceral groups for these formations are as follows (in %): 27-100 vitrinite (average 77), 0-73 inertinite (18), and 0-33 liptinite (8) for the Tyumen Formation; 52-100 vitrinite (average 82), 0-44 inertinite (14), and 0-48 liptinite (12) for the Vasyugan Formation. Consequently, the coals formed under approximately the same environmental conditions; the remains of higher plants - lignocellulose and more rarely lipid components - served as their source material. In this regard, Upper and Middle Jurassic coals have been poorly studied within the area under consideration. Analysis of the maceral composition of coals, along with lithological studies, contributes to understanding the environmental conditions of the formation of coal-bearing strata. These data may be useful for petroleum producers in developing hydrocarbon deposits for efficient underground coal gasification and further pipeline gas packing.
