Uwagi o paleogeograficznym i tektonicznym stanowisku niecki szczecińskiej

Ryszard Dadlez

Abstrakt


REMARKS ON PALAEOGEOGRAPHICAL AND TECTONIC POSITION OF THE SZCZECIN TROUGH (WESTERN POLAND) IN RELATION TO THE ADJACENT AREAS

Summary
The results of investigations carried out in the Szczecin trough area (seismic profiles and drillings located on anticlines) show the reduced profiles of Jurassic and Cretaceous deposits. This reduction is twofold in relation to the Western Pomerania and fourfold as for the Kujavian area.
The deposits of Upper Toarcian, Aalenian, Bajocian, Bononian, Purbeckian as well as of Lower Cretaceous, inclusively to the Aptian, are lacking there.
There are two possibilities of explanation of this reduction, viz.:
l. Such a development has a regional extent and is characteristic of the entire Szczecin trough. The sedimentation basin of the Szczecin trough, at the time discussed, was evidently more shallow than those of Kujavien and Southern Mecklenburg. Their connection through the Szczecin trough seems to be closed during the lower Dogger, uppermost Malm and Lower Cretaceous times. This fact makes the interpretation of connections between the basins of Western Europe and Middle Poland difficult, because the communication through the Western Baltic area may have been possible only during some periods (Oxfordian, Bononian and, in less degree, Neocomian).
2. The available profiles of the anticlinal structures may represent the local conditions that have originated as a result of the synsedimentary tectonic movements (Halokinese). The Jurassic profile in the synclines may be more complete, although the interpretation of seismic profiles does not indicate that, allowing to assume the changes in thickness only in the Upper Cretaceous deposits.
The changes in thickness should be also taken into consideration when studying the thickness of the region discussed. The structural difference between the Szczecin trough (with the Upper Cretaceous deposits) and the Pomeranian para-anticlinorium (with the Triassic and Liassic deposits) is the result of increasing of thickness in the direction of the later unit. Possibility of movements of salt mass, compensated by increasing of thickness of the overlain deposits, permit to assume that the recent complicated tectonics of Mesozoic is independent on the almost undifferentiated surface of pre-Zechstein substratum (alike as in Germany).

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