Leaders: M. Szulczewski, S. Skompski, A. Wańkiewicz
Fee: 160 €
The Holy Cross Mountains (HCM) are a relatively small area (90 x 30 km) of the Mid Polish Uplands, where the Palaeozoic strata are exposed to the surface, isolated by the Permian and Mesozoic systems from the other Palaeozoic exposures of Central Europe. As a distinct geomorphological and geological entity they are the result of post-Cretaceous epeirogenic activity and are situated just where the meta-Carpathian arch is crossed by the Middle-Polish rampart. The HCM are located between the Variscides of the Central Europe and the East European Platform, relatively close to the Tornquist-Teisseyre Tectonic Zone.
The Palaeozoic succession of the HCS contains all Palaeozoic stratigraphic systems, and for this reason the area is a traditional place of field courses not only for Polish, but also for German and Latvian students. Facies differentiation, relatively simple tectonic, and numerous fossiliferous sites make this area especially atractive for teaching of geology. Most complete and interesting is here Devonian succession. The sedimentation of a new syn-Variscan megacycle was started in the end of Early Devonian with the terrigenic sandy-shale formations. This type of deposition was relatively promptly (in the beginning of Eifelian) followed by carbonate sedimentation, which persisted nearly to the end of Frasnian. It was composed of the dolomitic and lime peritidal sediments in the lower part, and thick stromatoporoid-coral complexes in the upper one. The biostromal sedimentation in the beginning ("bank stage") was replaced by bioherms with detrital flanks ("reef stage") in the younger parts of the sequence. In the end of Frasnian and beginning of the Famennian the transgressive trends have been significantly differentiated. Simultaneously with general deepening of the sedimentary environments, the sharply bounded swells have been uplifted, sometimes emerged and then again covered by the marine sediments - extremely condensed (with stratigraphic gaps) crinoidal-cephalopod limestones.
During proposed field trip the most important turning points of this succession will be presented in four large quarries:
Lower Devonian off-shore to lagoonal clastics, tempestites, significance of early Devonian ichnofossils for sedimentological interpretation
Middle Devonian peritidal cyclicity, selective dolomitization, transgressive events as parasequences boundaries
Upper Devonian stromatoporoid mounds and drowning of the platform: neptunian dykes, stratigraphic condensation
M.-U. Devonian platform to basinal succession, redeposited limestones on the platform slope