The palynofacies pattern for the Lower Cretaceous of central Poland

Abstract

Sedimentary environments and palynofacies were identified in the Lower Cretaceous of central Poland. The study was based on lithological observations, sedimentological logging and palynological investigations in the following boreholes: Poddebice PIG2, Kolo IG3 and IG4, Wągrowiec IG1, Sarnow IG1, Ciechocinek IG3, Mszczonow IG1, Korabiewice PIG1, Czluchow IG2, Klosnowo IG1 and Tuchola IG1. Palynological observations were correlated with sedimentological, lithofacies and paleogeographical data. Sedimentary environments and palynofacies were analysed in the vertical section, and spatially in different areas: in the central basin area, in the carbonate-clastic deposition zone, in the transitional zone (deltaic sedimentation) and in a zone of an active salt pillow. The following sedimentary environments were identified in the Lower Cretaceous: upper shoreface and lower-middle shoreface with transitions to an offshore-open marine shelf, delta (?delta front) passing up into distributary channel fills on a delta plain, presumed barrier and shallow-marine embayment, lagoon and shallow carbonate-siliciclastic shelf. In case of the absence of diagnostic features for exact determination of sedimentary environments, the environments were defined as generally marine or transitional (probably deltaic). A maximum flooding surface has been identified in the Poddebice PIG2 section, represented by a thin dark-grey marl bed which seems to be dated at the Berriasian/Lower Valanginian transition. The relationships between sedimentary environments and the characteristics of the palynofacies spectrum were determined, and a palynofacies pattern for the Lower Cretaceous of central Poland was proposed in a tabular form.