Próba ustalenia budowy zapadliska przedkarpackiego w granicach Polsk

Abstract

AN ATTEMPT AT ESTABLISHING THE STRUCTURE OF THE CARPATHIAN FORE-DEEP WITHIN THE AREA OF POLAND

The area of the Carpathian fore-deep has a highly complex geological history. After the folding process having taken place at the Precambrian time, in the Assynthian phase, the area was elevated. The sedimentation of the Cambrian deposits was on the northern side of the area, and then the deposits were folded, and the folds directed towards WNW-ESE. Both Ordovican and Silurian periods are characterized by several sedimentary breaks and by distinct overfolds. The Devonian deposits developed in the Old Red facies, and within the westerly part - in a marine sandstone facies, were laid down on various older members. Later on, the Devornian was followed by the organic movements of the Bretonian phase. The folded Devonian formations were overlain from NW and N by the Tournaisian deposits at the time of the Sudetic phase. The Visean deposits were subject to a strong disturbance. At present, several units may be distinguished, running in a similar direction as the folds of the Święty Krzyż Mts. At the Upper Carboniferous time, the stress caused by the displacement of both the Moravian and the Sudetic massifs, was responsible fool the tectonic movements resulting in dislocations of a NS or NE-SW direction. Most probably, at the decline of the Carboniferous and at the beginning of the Permian times, a change in the directions of foldings took place. During the Triassic and the Middle and Upper Jurassic times, the direction of the Święty Krzyż - Dobrudja swell became stable. At the Upper Cretaceous period the transgression approaching along the Miechów trough and the Lublin lowland emboss the swell. The last Miocene transgression probably that of the Burdigalian and Helvetian, had filled up the fore-deep that, later on, was covered by the overfolded Carpathians. The Tortonian and Sarmatian deposits laid down within the northerly displaced fore-deep were then folded along the margin of the Carpathians.