Geologic and Geochemical Features of the Upper Devonian Coals of the North Timan (the Sula River Coal Field)

Abstract —The composition of the oldest coals of the Timan–northern Urals region has been studied comprehensively, and their hydrocarbon and microcomponent characteristics are given. The relationship between different types of coals and Late Devonian plant communities of the North Timan is revealed. It is also determined that some samples contain microspores, megaspores, and plant remains belonging mainly to the lycopod Helenia. The most probable source of jet coals is identified as the wood of the progymnosperm Callixylon. The values of vitrinite reflectance and Tmax and the data on the distribution of polycyclic biomarkers and methylphenanthrenes indicate the low maturation of the coal organic matter. The coal bitumen investigated here is characterized by the dominance of steranes and diaster-13(17)-enes of compositions C28 and C29. The following diterpanes are identified: beyerane, 16α(H)-kaurane, 16β(H)-kaurane, and 16α(H)-atisane. At the same time, phyllocladane is absent.