Problem granicy namur-westfal w północno-zachodniej części niecki śródsudeckiej

Abstract

NAMURIAN-WESTPHALIAN BOUNDARY IN THE NORTH-WESTERN PART OF THE INTRA SUDETIC TROUGHSummaryThe article presents the results of studies based on the conclusions drawn mainly from the palynological analyses of the Biały Kamień beds, and of the upper member of the Walbrzych beds from the NW part of the Intra-Sudetic trough. The area covered with palynological sections is presented on Fig. 1. The results of the palynological examinations and previous opinions as to the stratigraphy and sedimentation of the series under consideration are given in Tab. 2.The palynological examinations have demonstrated that:1 – top part of the Wałbrzych beds should be regarded as an equivalent of the Lower Namurian B. It has been ascertained on the basis of macrofloristic studies that the Wałbrzych beds correspond to the Lower Namurian (W. Gothan, W. Gropp, 1933);2 – accumulation of the Biały Kamień beds embraced a time interval between the Upper Namurian Band Lower Westphalian A, inclusive;3 – microfloristic studies did not prove the presence of the so-called “floral break” between the Lower and Upper Namurian. Spore material points to a slow disappearance of certain species, and to an appearance of other ones towards the upper members of the Carboniferous deposits;4 – the microfloristic material gathered did not attest the opinions of certain geologists that the Upper Carboniferous sedimentation had begun, within the area  situated west of the Wałbrzych Basin, at the Westphalian time, in connection with the Erzgebrige phase. The equivalents of the Namurian B in the Wałbrzych Basin and in the western part of the lntra-Stidetic trough point to a fact that at  that time both regions were an accumulation area;5 – it appears that the disturbances corresponding to the Erzgebirge phase were rather of vertical nature; the sediment here accumulated proves that this old accumulation area did not undergo any uplifting, but was a depression filled in with terrigenous material. Although erosion connected with an increased competence of streams could have taken place in some regions, but, generally, an uninterrupted accumulation persisted from the Wałbrzych beds, up to the Biały Kamień beds, as it can be seen in both micofloristic assemblages and lithology observed in the area under consideration.