Stan litostratygrafii epikontynentalnej dolnej jury w Polsce i propozycje jej usystematyzowania

Abstract

Przedstawiono, przedyskutowane w zespole specjalistów, propozycje uporządkowania litostratygrafii epikontynentalnej dolnej jury w Polsce. Na tle aktualnego stanu litostratygrafii (tab. 1) zaproponowano dwa warianty uproszczonego podziału, przy czym postanowiono, że pierwszy z nich (tab. 2) stanowić będzie podstawę dalszych prac nad sformalizowaniem podziału (ustanawianie stratotypów).  STATE OF LITHOSTRATIGRAPHY OF THE EPICONTINENTAL LOWER JURASSIC IN POLAND AND PROPOSALS FOR ITS SYSTEMATIZATION Within the activities of a special working group sponsored by the Polish Academy of Sciences and aimed at the systematization of the lithostratigraphic subdivisions in Poland, the works concerning the Lower Jurassic sequence have also been taken up. They are based upon the recently edited Polish Stratigraphical Code (S. Alexandrowicz, K. Birkenmajer, J. Burchart et al., 1975). Lithostratigraphic subdivision of the epicontinental Lower Jurassic sediments in Poland is a traditional one since these sediments are developed mainly in the limnic-brackish facies (Figs. 2–5). Eight local subdivisions with more than thirty local stratigraphic units are in current use now (Figs. 1-5), However, some of them are correlatable between the neighbouring areas – they constitute probably a single rock body and could be uniformaly denominated.On the basis of the existing subdivisions (Tab. 1), two versions of proposals have been put forward by the author for the sake of this uniformity. After thorough discussions within a team of specialists (the results of these discussions are presented in the paper), the first version has been accepted (Tab. 2) reducing to 21 the number of lithostratigraphic units. It is taken as a scheme and starting point for future investigations. The same team of specialists will define the type sections in the ne1xt few years.The second, more' simplified version (Tab. 3) has been treated as a future one. It needs further elaboration and better recognition of the spatial relationships between rock bodies.