Cykliczność sedymentacji pokładu 664/665 warstw wałbrzyskich (DZW)

Krzysztof Mastalerz, Maria Mastalerz



A purpose of this paper was to detect a cyclic structure of a coal seam on the background of macroscopic profiling only. Six detail profiles for individual sites of No. 664/ /66) coal seam of the Wałbrzych Beds, Intra-Sudetic Basin have been investigated. An embedded Markov chain method has been used to test a (coal) lithotype sequence of this seam. The date were transformed into four state system. A set of lithotype succession shows cyclic characteristic with a one-step dependence in the chain.
Peat-(coal-)forming accumulation following a phase of clastic sedimentation starts usually with fine clarain (lithofacies F). It represents a reed moor environment of the peat bog development with plants adopted to relatively deep water cover. Next state in the cycle - durain (lithofacies D) - represents mostly allochtonous deposits of a plant material which seems to be remnants of a previous decay in oxidized conditions. This conclusion seems to be confirmed by microscopic studies. Following element of the cycle - coarse clarain (lithofacies C) represents a forest moor type of the peat bog subenvironments. It indicates relatively drier conditions and probably arborescent type of plant. Dirt hands - mostly mudstones (lithofacies M) finish interseam cycle development. They are a result of flood events and seem to be restricted to vicinity of natural levees.
The cyclicity is a response of changes of the flood plain sedimentation due to internal processes within the alluvial plain environment. The role of external factors (e.g. subsidence) appears to be only indirect.

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