Geologiczna mapa Bałtyku
Abstract
GEOLOGICAL MAP OF THE BALTIC
Summary
The map of Cenozoic subcrops of the Baltic Sea was compiled within the framework of preparation of the map of Poland and adjoining areas in the scale l : l 000 000. The changes in relation to previous sketches and maps are primarily limited to the southern Baltic. The studies carried out in the last few years showed that the Bornholm horst is separated from Scania by large fault zones (Andersen et al. 1975). Geological boundaries from SE slope of the Baltic shield should be treated as tentative and minimum as it is possible to expect the occurrence of erosional patches or even thin continuous cover which is difficult to trace by geophysical methods, outside of continuous belts of outcrops marked here. This is especially the case of the Upper Cretaceous which rests on Triassic and even older formations west of 18 °E.
The structure of Cretaceous cover appear monotonous in the western Baltic and Danish islands where an almost continuous Maestrichtian cover is not divided by Laramic movements. Attention should be paid to a zone of very strong Late Cretaceous subsidence, where completely developed Upper Cretaceous section is more than 750 m but less than 2000 m thick. This zone disappears in the Baltic where the Mid-Polish anticlinorium is rising and it reappears in somewhat modified form in Poland. Close to the Polish coast the anticlinorium divides into three branches, two of which retain the NW-SE direction and soon disappear and the third, western one, passes into the Greiswald anticline and, probably, the Ringköbing-Fyn High west of Rügen, delineating the Baltic part of the Danish-Polish anticlinorium from the south-west. From the north-east the Danish-Polish trough is delineated by giant fault zones continuing from Scania to Poland.
Summary
The map of Cenozoic subcrops of the Baltic Sea was compiled within the framework of preparation of the map of Poland and adjoining areas in the scale l : l 000 000. The changes in relation to previous sketches and maps are primarily limited to the southern Baltic. The studies carried out in the last few years showed that the Bornholm horst is separated from Scania by large fault zones (Andersen et al. 1975). Geological boundaries from SE slope of the Baltic shield should be treated as tentative and minimum as it is possible to expect the occurrence of erosional patches or even thin continuous cover which is difficult to trace by geophysical methods, outside of continuous belts of outcrops marked here. This is especially the case of the Upper Cretaceous which rests on Triassic and even older formations west of 18 °E.
The structure of Cretaceous cover appear monotonous in the western Baltic and Danish islands where an almost continuous Maestrichtian cover is not divided by Laramic movements. Attention should be paid to a zone of very strong Late Cretaceous subsidence, where completely developed Upper Cretaceous section is more than 750 m but less than 2000 m thick. This zone disappears in the Baltic where the Mid-Polish anticlinorium is rising and it reappears in somewhat modified form in Poland. Close to the Polish coast the anticlinorium divides into three branches, two of which retain the NW-SE direction and soon disappear and the third, western one, passes into the Greiswald anticline and, probably, the Ringköbing-Fyn High west of Rügen, delineating the Baltic part of the Danish-Polish anticlinorium from the south-west. From the north-east the Danish-Polish trough is delineated by giant fault zones continuing from Scania to Poland.