Znalezisko Manticoceras adorfense Wedekind a problemy dewonu górnego na Lubelszczyźnie

Abstract

THE FINDING OF MANTICOCERAS ADORFENSE WEDEKIND AND THE PROBLEMS OF THE UPPER DEVONIAN IN THE LUBLIN AREASummaryGoniatites Manticoceras adorfense W d k d have been found in bore hole Opole Lubelskie IG-l, situated approximately 50 km west of Lublin. This is the first finding place of these goniatites in the eastern area of Poland.The bore hole Opole Lubelskie IG-l is located, within the Radom – Kraśnik elevation, where the Devonian formations are overlain with the Mesozoic ones.About 3 km north-east of the bore hole a fault of a NW-SE direction rum. Behind this fault the Mazowsze – Lublin rift occurs, where the Devonian is covered with the Carboniferous formations characterized by a considerable thickness (Fig. 1). The Upper Devonian section in the bore hole considered is as follows (Fig. 2).At a depth of 985.0–1145.0 m are found Famennian formations. These begin with the Niedzwica Beds (985.0–1085.7 m) – grey calcareous clays with Genuclymenia sp. (1046.0 m), grey marls, subordinately also calcareous sandstones. Below (1085.7–1120.0 m) there rests a series of nodular limestones, mainly conglomerate-like nodular limestones which at a depth of 1120.0-1140.0 m pass into a series of banded limestones (dark-grey marls with pelitic limestone intercalations). From 1145.0 m to 1473.0 m there occur Frasnian formations represented by a calcareous-coralline series, at the top by detrital limestones with Manticoceras adorfense W d k d. (1149.5 m); below there are limestones with numerous coral representatives and stromatoporoids·.The goniatites Manticoceras no doubt prove the presence of the I goniatite horizon here. The fact of goniatite occurrence at the top of the Frasnian section can be a sign of stratigraphical condensation related to a reduction in subsidence caused by the first effects of the Bretonian phase within the palaeoanticlinal area of Opole Lubelskie. The author is of an opinion that the sedimentation of the series of banded limestones (II goniatite horizon) may have begun earlier hi the Lublin rift than within the Opole Lubelskie palaeoanticline. In this connexion the Frasnian-Famennian boundary, drawn at the bottom of the series of banded limestones, is probably of heterochronous nature. The sedimentation of the marly-calcareous deposits of Famennian age is an evidence of the increased erosion of the alimentation area, due to the activity during the Bretonian phase. At the Famennian time the erosion was of particular intensity in the central part of the Mazowsze-Lublin rift, as compared with the Opole Lubelskie area. The presence of Genuclymenia sp. in the Niedrzwica Beds, pierced by bore hole Opole Lubelskie IG-l, proves that the emergence and the erosion of the Opole Lubelskie region took place not earlier than in the V goniatite horizon.