Coalification, coal facies and depositional environment of the 9th to 12th coal seams of the Jan Šverma Mine Group, Lampertice Member (Intra-Sudetic Basin, Czech Republic) from the view point of coal petrology

Abstract

Four subsequent coal seams of the Žacléř group, the Intra-Sudetic Basin, have been studied petrographically, and geochemically to determine paleoenvironment conditions of their formation. The Intra-Sudetic Basin, situated around the Czech-Polish border, represents intracontinental basin filled dominantly with fluvio-lacustrine strata of the Mississipian to Triassic age. Coal seams under investigation are composed of banded coal having ash content between 15.3 and 19.74%. The rank of coal corresponds to high volatile bituminous (A) class. H/C versus O/C diagrams show position of the studied coal in the area of vitrinite genesis pathway which is indicative for its precursor formation from woody material of arborescent plants. They also occur within the field of type-III kerogen (kerogen-type diagram) at the mature zone of catagenesis representing bituminization stage of coalification. The C/N ratios of the measured samples have high values from 68 to 102 typical for formation from lignin-rich vascular plants. Most common of coal samples having ortho-hydrous and pre-hydrous characters give an evidence of dominance of anaerobic conditions of medium to low redox potential. Macroscopic characteristics denote the improvement of coal quality and depositional environment toward the upper coal seams. Thick...

Four subsequent coal seams of the Žacléř group, the Intra-Sudetic Basin, have been studied petrographically, and geochemically to determine paleoenvironment conditions of their formation. The Intra-Sudetic Basin, situated around the Czech-Polish border, represents intracontinental basin filled dominantly with fluvio-lacustrine strata of the Mississipian to Triassic age. Coal seams under investigation are composed of banded coal having ash content between 15.3 and 19.74%. The rank of coal corresponds to high volatile bituminous (A) class. H/C versus O/C diagrams show position of the studied coal in the area of vitrinite genesis pathway which is indicative for its precursor formation from woody material of arborescent plants. They also occur within the field of type-III kerogen (kerogen-type diagram) at the mature zone of catagenesis representing bituminization stage of coalification. The C/N ratios of the measured samples have high values from 68 to 102 typical for formation from lignin-rich vascular plants. Most common of coal samples having ortho-hydrous and pre-hydrous characters give an evidence of dominance of anaerobic conditions of medium to low redox potential. Macroscopic characteristics denote the improvement of coal quality and depositional environment toward the upper coal seams. Thick...