Nowe dane o faunie warstw ostrawskich (namur A) w rejonie Katowic

Abstract

NEW FAUNISTIC DATA ON THE OSTRAVA BEDS (NAMURIAN A) IN THE KATOWICE REGIONThe article presents a stratigraphic-faunistic description of the Carboniferous formations found by the bore hole Wełnowiec, near Katowice. The bore hole has been depended to a depth of 1504 m, and the Upper Carboniferous (Namurian A) deposits have been encountered. Faunistic material taken for examination consists of 770 specimens representing all the animal groups, which are known to occur in the productive Carboniferous of the Upper Silesian Coal basin. Both numerous fossils and the greatest differentiation in species have been ascertained in the fauna-bearing intercalations occurring at the interval down to a depth of about 400m. The intercalations contains mainly marine fauna. At the depths 400 m to about 870 m both fresh-water and salt-water faunas have been ascertained. Here, numerous species occur, characteristic of Namurian A deposits. The lower part of the section reveals smaller amount of fossils. Only at the depth of about 1110÷1400 m there occur three intercalations bearing single specimens of marine pelecypods. The individual stratigraphical members of the Wełnowiec section (in Namurian A) are as follows: Poręba beds from 0,0 to 320,60 m with the faunistic zones Id, II, III, V; Jaklowiec beds occurring  at a depth of 320,60÷378,40 m, lacking fauna; Gruszów and Pietrzkowice beds frequently determined by  a common term – the Lower Ostrava beds. They occur from the depth of 378,40 m. The lower boundary of these beds cannot be drawn, mainly due to a poor fauna assemblage and a lack of typical species. At the top of the Gruszów beds the zone VII occurs, bearing marine fauna. In the lower portion of the beds fresh-water lingual fauna occurs, and the successive 240 m thick series does not contain any fossils. In the bottom part of the deposits pierced by the bore hole considered, some marine pelecypods have been found, too. Except for one specimen Anthraconeilo transversalis (Kleb.), so far known from the Namurian A of both the Upper Silesian and the Lublin Carboniferous, only long-lived species occur there. In connection with this, an opinion has been approved that this member also belongs to the Namurian A. The stratigraphical nomenclature that has been accepted for the deposits of Namurian A, pierced by the bore hole Wełnowiec, is applied to the western and middle parts of the Upper Silesian Coal Basin. However, for the eastern part of the Basin another stratigraphical nomenclature is used for Namurian A. In consequence of this, a correlation has been made between these two subdivisions in the section of Wełnowiec (Fig. 3). At the depths from 0,0 to 378,40 m the Grodziec beds have been distinguished. They correspond to both Poręba and Jaklowice beds (upper part of the Ostrava beds). In the lower part of these latter, there occur, at the depths from 378,40 to 870,00 m the Florów beds, characterized by fresh-water lingual fauna. Below, down to a depth of 1110,00 m, there are found the Sarnowo beds lacking fauna and coal seams. The lowermost deposits ascertained here by drilling have been determined as the Malinowiec beds. Their bottom part probably corresponds to the lower-most portion of the Namurian A deposits.