Elementy analizy facjalnej w zastosowaniu do korelacji jednostek litostratygraficznych silezu i autunu w Sudetach Środkowych

Abstract

THE USE OF ELEMENTS OF FACIES ANALYSIS IN CORRELATION OF SILESIAN AND AUTUNIAN LITHOSTRATIGRAPHIC UNITS IN THE CENTRAL SUDETY MTS. Summary Conglomerate and sandstone layers were identified in the Autunian and Silesian packets encountered in five deep boreholes (boreholes Lubawka IG-1, Grzędy IG-1, Unisław IG-1, Głuszyca IG-1, and Rybno S-5) in the Intra-Sudetic Depression (Fig. 1). The coarse clastic layers were plotted as points in the graph (Fig. 2, right side). Numbers of successive layers in a section (from the top downwards) are marked at the vertical axis of the graph, and thickness of the layers - at the horizontal axis. The data were subsequently subjected to a smoothing procedure (by the mobile mean method) and the obtained values plotted in the graph and connected with continuous line (thick line in Fig. 2). The obtained curves are presented at the background of lithostratigraphic subdivision (Fig. 2 and Table). The comparison of curves obtained for individual borehole columns made it possible to draw the following conclusions: 1) The curves show that increase in transport capability of rivers supplying clastic material to the Intra-Sudetic basin was first marked in a local basin of the Wałbrzych Depression (borehole Grzędy IG-1) and, subsequently, in areas south-east and west of the depression. 2) This shows that development of sedimentation in the Intra-Sudetic coal basin has been controlled by the tectonics. A decisive role of climatic factor would be reflected by identical position of thickness maxima in all the studied borehole columns. 3) The analysis of curves of thickness of coarse-clastic layers (channel sediments) failed to give any unequivocal evidence for more precise drawing of boundaries of lithostratigraphic units. The boundaries should be drawn taking into account also some other features of sediments and paleontological record. 4) Elaboration and introduction of more diversified research methods appear necessary for correlation of lithostratigraphic units.