Profil liasu w Krośniewicach (Kujawy)

Ryszard Dadlez



Recently, an interesting complete Liassic section, 1171 metres in thickness, has been ascertained when drilling at Krośniewice, Kujawy region, Central Poland. Location of bore hole is shown on Fig. 1, and schematic lithological section is presented in a comparison with the adjacent ones on Fig. 2. A correlation of lithological complexes and of sedimentary cycles is made with the section previously investigated in the vicinity of Kłodawa (S. Z. Różycki, 1958). Age of the deposits has been determined after a correlation with the areas of West Poland using scarce fauna remains encountered during examinations. In 68 samples especially investigated, no megaspores have been encountered. The section under consideration is of type inland nature, and only lamellibranchs of the genus Cardinia may point to certain feeble influence of brackish environment in the beds ,thought to be equivalents of Carix, and Estheria fauna - in the beds of Lower Toarcian age. Regional conditions are better represented by the Krośniewice section than by the Kłodawa sections which occur within the aureole of a salt dome and, therefore, might have been subject to stronger local halokinetic processes which disturbed normal sedimentary cycle. Here, the part of clay rocks is fairly considerable, greater than in the region of Kłodawa. Sedimentary cycles begin here with white and light grey quartz sandstones, locally of coarsegrained character, and end with grey and dark grey, subordinately (Lower Toarcian) also grey-green mudstone-clay rocks. Maximum thickness of Liassic formations in Kujawy (Fig. 1) may amount, according to the results obtained during seismical surveys, to 1500-1600 metres.

Full Text:

PDF (Polish)