Carboniferous coarsening-upward and non-gradational cyclothems in the Lublin Basin (SE Poland): palaeoclimatic implications

Abstract

Abstract The paper presents the characteristics of profiles consisting of coarsening-upward and non-gradational cyclothems that correspond to parasequences in the Visean, Serpukhovian and Bashkirian sections of the Lublin Basin in SE Poland. The accompanying single fining-upward cyclothems are also described. Six types of cyclothems are distinguished. The most complete types of coarsening-upward cyclothems Ic, Id and incomplete IIc and IId have been identified. The least complete are non-gradational cyclothems IIIc and IIId. The cyclothems developed within the oscillating environments of shallow carbonate and clay shelf, and in shallow-water deltas. The lowstand systems tract (LST) deposits are composed of fining-upward cyclothems, rarely of coarsening-upward IId and non-gradational IIId. Within the transgressive systems tract (TST), type IIc is dominant, and the quantity of Ic and non-gradational cyclothem IIIc is moderate. The maximum flooding surface (MFS) usually occurs within coarsening-upward cyclothems IIc. The highstand systems tract (HST) consists of similar types of cyclothems as the TST, but their quantity is less. Relative sea-level fluctuations during the Carboniferous deposition in the Lublin Basin are associated with sea-level changes generated by glacial episodes in Gondwana. The relative sea-level fluctations also affected both erosional processes related to the successive relative sea-level lowstands and the formation of stratigraphic gaps. The influence of glacio-eustatic fluctuations was modified by local factors such as the supply of sedimentary material, subsidence rate and local tectonics.