Silurian graptolite biostratigraphy in the Wojcieszków 1 borehole and its significance for the stratigraphic correlation on the Lublin Slope of the East European Platform, Poland

Abstract

On a deep shelf of the marginal part of the East European Platform in Poland the flat-lying Silurian succession is represented by the siliciclastic sedimentary rocks with graptolites. In the Wojcieszków 1 well some of the Silurian graptolite biozones have been documented assigned to Llandovery, Wenlock, Ludlow and Pridoli, including most of its stages. The stratigraphic gap in the base of the Silurian spans the lower part of the Rhuddanian. The Jantar Formation is dated by Atavograptus atavus-Coronograptus cyphus interval indicating upper Rhuddanian age. The age of the Pasłęk Formation is defined as the Aeronian and Telychian, based on the graptolite biozones from Demirastrites triangulatus to Cyrtograptus insectus. The next major gaps in the biostratigraphic record are found in the Telychian. These gaps are related to the environmental changes during the sedimentation of the Pasłęk Formation. The biochronostratigraphy of the Pelplin Formation is based on the assemblage of the ?latest Llandovery, Wenlock and Ludlow graptolites. All Homerian and three Gorstian biozones have been documented in the profile, along with the so-called “Cucullograptus Band”. The deposition of coarse-grained siliciclastics of the Kociewie Formation begins in the Lobograptus scanicus Chron of the latest Gorstian. The interval with Bohemograptus documents the lower Ludfordian part of the Kociewie Formation. The Silurian ends with the Puck Formation of the Pridoli series. The distribution of the graptolite biozones and the chronostratigraphic succession of lithostratigraphic units correspond closely to the developmental pattern of the Baltic Basin in the marginal East European Platform.