O stratygrafii kambru platformowego w Polsce

Abstract

STRATIGRAPHY OF PLATFORM CAMBRIAN DEPOSITS IN POLANDSummaryIn Poland the deposits of the platform Cambrian represent both Lower and Middle Cambrian (Fig. 1). The maximum thickness of these deposits amounts to about 680 m, approximatelly 560 m falling on the Lower Cambrian (Fig. 2). On the fauna remains, found to occur in these deposits, the Lower Cambrian may be subdivided into three horizons as follows Sub-Holmia horizon, Holmia horizon, and Protolenus horizon. On the other hand, the Middle Cambrian is represent by the stage Paradoxides oelandicus only.The Sub - H o l m i a  h o r i z o n is developed as sandstones with few intercalations of siltstones and claystones. The deposits of this horizon disclose rich fauna representatives of the following genera: Torellella, Hyolithellus, Discinella = Mobergella, and Platysolenites. At places, the species of these genera, found to occur within the area of Poland, are analogous to the species encountered in the area of Scandinavia and in the Baltic countries, even in Greenland and Siberia.The H o l m i a and P r o t o l e n u s horizons are built by a series of arenaceous-siltstone-clayey deposits that reveal disturbed structure. To these deposits contain rich trilobite fauna. To the richest genera belong here Holmia and Strenuaeva, which point to a close relation with the Scandinavia. At the top of this series, i.e. already in the Protolenus horizon, are found species that belong to the genera reported from the Mediterranean zone.M i d d l e  C a m b r i a n is developed as sandstones. Fauna that occurs in the sandstones, particularly the form Ellipsocerphalus polytomus, proves that the sandstones may be referred to the stage Paradoxides oelandicus, and may be related with the area of Scandinavia. At the top these sandstones there are found numerous representatives of Scolithus, like in the Tiskarlan sandstones of Middle Cambrian age in Estonia.In the north-eastern area of Poland, the Middle Cambrian is covered with the transgressive deposits of Lower Arenigian age.