Paleomiąższość, litofacje i paleotektonika noryku i retyku na Niżu Polskim

Abstract

 Mapy paleomiąższości i litofacji osadów noryku i retyku odzwierciedlają rozwój basenów sedymentacyjnych w tym okresie. Na podstawie tych map dokonano analizy paleotektonicznej, która ujawniła, że na formowanie się paleostruktur w noryku i retyku największy wpływ wywarły ruchy tektoniczne na przełomie kajpru górnego i noryku oraz retyku i jury dolnej.

PALAEOTHICKNESS, LITHOFACIES AND PALAEOTECTONICS OF THE NORIAN AND RHAETIAN IN POLISH LOWLAND

Palaeothickness and lithofacies maps of the Norian and Rhaetian sediments in Poland (beyond the

Carpathians) reflect the sedimentary basin evolution in this period (Figs 1, 2). Based on these maps a palaeotectonic map showing the Norian and Rhaetian base at the close of Rhaetian sedimentation has been elaborated (Fig. 3).

The Late Triassic tectonic movements in the discussed area were mostly marked at the boundary between Upper Keuper and Norian. In several regions there is a gap between these stages including the defferent beds of Keuper, and at places the earlier Triassic sediments as well as undefined rocks of

Norian.

The periods of increasing and decreasing tectonic movements were variable in different regions.

A differentiated degree of erosion of the Norian substratum on the positive structural elements points to the fading of these movements in various times. It is impossible to determine exactly when they faded out in such a region, since the sediments of Norian cover on these elements are not subdivided in detail.

Exceptional are only the palaeostructures which were being uplifted during the Norian and were covered by the Rhaetian sediments. Nevertheless a distinct influence on the final formation of the Norian and Rhaetian palaeostructures had also the tectonic movements at the boundary between the Rhaetian and Lower Jurassic.