Mapa tektoniczna SW brzegu platformy wschodniej Europy (IGCP-86) - Uwagi i impresje

Jerzy Znosko



A solemn final session of the IGCP project no. 86 - "SW Border of East European Platform", which was held in Potsdam on the 2nd and 3rd of April, 1986 has been discussed in the present paper. Geologist from German Democratic Republic were strongly represented besides the representatives of 10 countries which participated in realization of the project. Sixteen reports were delivered to the session. Polish geologists were the authors and co- authors of four lectures. However it mainly concerned the remarks, reflections and impressions which resulted from the entire scientific session held in Potsdam as well as from the international cooperation and discussion at the compiling of the tectonic map.
1° - there is a salient contrast between creating (and representing on the map) some tectonic units or important geological events and the recent state of knowledge. For example East Łaba Massif has been strictly defined as redards tectonics and age, although nobody has never even touched a rock sample derived from it; 2° - hastiness of "transplantation" of recent structural feature of the Earth's crust and Moho discontinuity to entire Mesozoic and Paleozoic and even Precambrian; moreover the conclusions drawn from this premise are based implicitly on the geological model which seems to be constructed as if nothing essential of fundamental has happened since Precambrian period; 3° - neglectfulness of the principles of actualism with regard to the earlier phases of geological progress which developed under the same physical and chemical laws nevertheless the quantity ratio could have been different than today.
Concerning the above premises it should be emphasized that the Upper Silurian flysch encountered within the Teisseyre-Tornquist zone should be reflected by tectonic implications within the area of Caledonian consolidation. The second problem deals with the large-scale transcontinental wrench movements along the Teisseyre-Tornquist zone although the trilobites belonging to the Baltic province are f o und on both sides of this zone. The third question concerns the interpretation of the erosional boundary of the Caledonian overthrust front in Middle Europe and Scandinavia. The matter needs revision in the light of new data derived from boreholes drilled in North Sea and Ringkc,6bing-Fionia Massif. And the last, fourth problem appears with the character of the floor of the "Teisseyre- Tornquist sea" that should have been oceanic in type, according with the results of geophysical research performed in T-T zone, which point to the remains of possible subduction. The same conclusion is drawn from the results of geological investigations carried out in Sudety Mts, where the complete ophiolitic sequence is associated with old Paleozoic rocks. T - T zone could have been a marginal, near-cratonic part of a vast oceanic basin.

Pełny tekst: