Lithologic sequences in the Upper Silesia coal-measure (Upper Carboniferous, Poland)
Abstract
Sekwencje litologiczne w utworach Górnośląskiego Zagłębia Węglowego
Vertical lithologic variability of the three chosen coal-bearing lithostratigraphic units was investigated using Markov chain analysis on the data from six deep boreholes. The relatively coarsest deposits appear randomly and initiate the sequences in path diagrams in all three units. In the Mudstone Series (deposits of an alluvial plain of meandering rivers) all lithologies are connected by transition paths and constitute one sequence. In the Poruba Beds (deposits of an alluvial plain and subordinately of mixed continental-marine environments) and in the Łaziska Beds (dominated by deposits of braided-rivers alluvial plain) also structureless fine-grained deposits appear randomly and have upwards transitions into rooty layers and coal. Thus two independent subsequences are distinguishable in these units: the „barren” (fining-up wards) and the „coal-bearing” ones. The position of the relatively coarsest clastics in the paths diagrams is interpreted chiefly as a result of river channel shifting and is related to intrabasinal factors. The occurrence of independent coal-bearing suhsequences is attributed to the intervention of extrabasinal factors.
Vertical lithologic variability of the three chosen coal-bearing lithostratigraphic units was investigated using Markov chain analysis on the data from six deep boreholes. The relatively coarsest deposits appear randomly and initiate the sequences in path diagrams in all three units. In the Mudstone Series (deposits of an alluvial plain of meandering rivers) all lithologies are connected by transition paths and constitute one sequence. In the Poruba Beds (deposits of an alluvial plain and subordinately of mixed continental-marine environments) and in the Łaziska Beds (dominated by deposits of braided-rivers alluvial plain) also structureless fine-grained deposits appear randomly and have upwards transitions into rooty layers and coal. Thus two independent subsequences are distinguishable in these units: the „barren” (fining-up wards) and the „coal-bearing” ones. The position of the relatively coarsest clastics in the paths diagrams is interpreted chiefly as a result of river channel shifting and is related to intrabasinal factors. The occurrence of independent coal-bearing suhsequences is attributed to the intervention of extrabasinal factors.