| Summary: | THE TECTONIC SETTING OF POLAND IN THE LIGHT OF THE STUDIES ON THE NORTH SEA AREA Summary The recent papers of P. A. Ziegler (1975) and W. H. Ziegler (1975) markedly contributed to the knowledge of geological evolution of the central and western Europe and thus, of the extra-Carpathian Poland. The main theses are as follows: (1) The metamorphic basement of the north-western Poland may be more reliably dated at the Dalslandian as the older basement of the neighbourhood of the southern North Sea was shown to be of that age. (2) The commonness at the Celtic (= Cadomian = Old Baikalian) orogeny throughout the England, Belgium and Brittany and the lack of it in the Ireland, Scotland and Norway indicate the tectonic affinity between the younger basement of Poland and the former region and not with the areas of Scottish-Norwegian Caledonian geosyncline (Fig. 1). (3) The above conclusion is supported by the results of the analysis of the development of the Silurian and Ordovician which do not display any uniform miogeosynclinal character in the areas adjoining the southern North Sea (Fig. 2). (4) The north-European basin (the North Sea basin in a wider sense) is epi-Variscan. It is delineated by the Caledonian orogen on the north-west, Variscan on the south, and by the margin of the Old Platform on the north-east. Poland is situated in its SE corner where the two latter features, Variscan orogen and the margin of the Old Platform, converge. The features first converge at the meridian of Rugia Island and to the east of it the basin of the Rotliegendes becomes narrower, shallower, and evaporite facies disappears. (5) Ringkøbing Fyn swell is epi-Variscan or older; it extends from Scotland on the west to Bornholm on the east. (6) The formation of aulacogens, great gravitational tectonic synsedimentary troughs set subperpendicular to the front of the Variscides, has started in the Permian. The strikes of the aulacogens and sutures in the crystalline basement coincides. This took place in the taphrogenic stage of the evolution of that region. (7) The southern part of the basin was subjected to compression accompanied by horizontal shitting along faults at the end of the Mesozoic during the Laramie phase. This resulted in the uplift, (inversion) of the areas of the troughs. The translocations related to the movements in the Tethyan areas and the formation of the Atlantic rift west of Europe was SE-NW oriented. This was the end of the taphrogenic stage. (8) The spreading of the north Atlantic bottom became more intense since the Eocene. At that time troughs from the area of the north-European basin disappeared and the part of the basin stretching east of Jutland emerged and became more rigid. The North Sea basin became narrow, meridional, and achieved the character of syncline. Poland is situated in a completely stabilized area outside the syncline.
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