Middle Devonian conodonts and structural implications for Świętomarz- Śniadka section (Holy Cross Mountains)

Abstract

The paper presents a new interpretation of the geological structure and stratigraphy of the Devonian in the Świętomarz–Śniadka section. The uppermost Śniadka Formation (equivalent to the Nieczulice Formation), was described previously from the northern part of the section between exposures of the sandstones and shales of the Świętomarz Formation. The present study revealed the presence in the mentioned area of Sitka Coral-Crinoid Limestone Member and the Sierżawy Member, referable to the Skały Formation. Black, thin-bedded limestones, occurring here, were assigned to the upper part of the Sierżawy Member. Conodont assemblages indicate that the Sitka Coral-Crinoid Limestone Member corresponds to the hemiansatus Zone, whereas most of the Sierżawy Member represents the timorensis – rhenanus/varcus zones. The presence of the North American species Icriodus janaea is documented for the first time in Poland. Clay shales and marls with Maenioceras terebratum are considered to be the uppermost part of the Sierżawy Member. These stratigraphic data are the basis for a new interpretation of the geological structure of the Bodzentyn Syncline.