Czerwony spągowiec w północno-wschodniej części basenu podlaskiego

Abstract

Zanalizowano pozycję stratygraficzną utworów zlepieńcowo-piaszczystych obszaru białowieskiego zaliczając je do czerwonego spągowca (najwyższego saksonu). Na podstawie cech litologicznych i sedymentologicznych skorygowano i uzupełniono obraz paleogeografii czerwonego spągowca w basenie podlaskim, wyznaczając·nowe walne elementy paleomorfologiczne. THE ROTLIEGENDES IN NORTH-EASTERN PART OF THE PODLASIE BASINConglomeratic-sandstone series was differentiated in borehole profiles from north-eastern part of the Podlasie Basin. These deposits were assigned to the Rotliegendes (uppermost Saxonian) taking into account distribution of thickness, lithofacies and heavy minerals. Figures 1-3 show stratigraphic position and lithology of this series.The profile of the conglomeratic-sandstone series comprises one or more simple, bipartite cycles of the conglomerate-sandstone type. Sandstones are sublithic arenites or lithic greywackes consisting of quartz (30–40%), feldspars (about 5%), rock debris (10%) and matrix (a few to 45%). Conglomerate pebbles vary in sorting. The share of fraction over 2 mm ranges from 30 to 50%. It consists of microcline (15–55%), vein quartz (5–25%), quartz sandstones and quartzites (0–5%), quartz-feldspar-muscovite gneisses (0–10%), granitogneisses (0–10%), and subordinate amounts of marly and strongly sandy limestones with single grains of gravel size.The occurrence of Rotliegendes rocks in the studied area is connected with a fairly large, NE–SW paleovalley (Figs. 4-5). The paleovalley was of tectonic origin, related to differentiation of the Precambrian basement. In the Rotliegendes times it was infilled with sandy and conglomeratic deposits of seasonal streams under arid or semiarid climatic conditions.