Dotychczasowe dane o budowie obszaru przedsudeckiego

Abstract

EXISTING DATA ON THE STRUCTURE OF THE FORE-SUDETIC MONOCLINF

The paper deals with the area assigned to the Fore-Sudetic monocline and the North-Sudetic swell which during the last years have been well recognized by drillings and seismical measurements. Within this area three structural stages: may be distinguished as follows: pre-Permian, Permo-Mesozoic and Cainozoic.

The structural pre-Permian stage cropping out on the sub-Tertiary surface·within the North-Sudetic swell is recognized by few drillings only. However, the results of these latter show the existence of metamorphic and magmatic rocks being analogous to those occurring in Sudetes. In the Fore-Sudetic monocline, the Carboniferous formations disclosing dips from 10 to 60° have been encountered in some bore holes piercing the pre-Permian stage (stages). The results of seismical cross section also demonstrate that the pre-Permian structural stage, at least·in the southern part of the Fore-Sudetic monocline, is folded in shape of anticlines·and synclines having a N-5 direction. This trend corresponds with the direction of folds found in the neighbourhood of the Sowie Mts. The folds have been reconstructed by K. Smulikowski and H. Teisseyre.

The Permo-Mesozoic structural stage is disturbed by faults disclosing amplitudes from tens to some hundred metres. Here, occur also flat and short anticlines, the amplitudes of which do not exceed, in general, some tens of metres; exceptionally they reach several hundred metres.

From the very he ginning of the Veriscian orogeny, up to the Palaeogene time, the Sudetes and the Fore-Sudetic area constituted a single massif. During the Permian and Mesozoic times this was an area of continuous accumulation processes which ended at the Palaeogene time. In that period a denudation process begun as a result of uplifting movements. After formation of the Sudetic marginal fault· throwing down its northern limb, the denudation persists only in the Sudetic area, and within the lowered forefield the Tertiary cover accumulates.