Rozwój rynny Miazgi–Wolbórki (Polska środkowa) w świetle analizy jej wypełnienia

Abstract

Formation of the Miazga–Wolbórka tunnel valley (central Poland) based on an analysis of its infill.A b s t r a c t. The subject of the analysis was a tunnel valley, weakly outlined in the landscape, located in central Poland, between Łódź and the Pilica valley to the west of Tomaszów Mazowiecki. The Miazga and lower Wolbórka flow along this valley. It is a 45-kilometre-long landform, mostly buried, partially covered with fluvial, slope and aeolian sediments, developed on a substratum characterised by varied palaeorelief and lithology. Sediments, which fill the valley, have variable thickness (10–100 m) and a non-flattened bottom gradient line, which indicates the possibility of water flow under hydrostatic pressure in a tunnel valley. Several segments of the channel cut into the Quaternary background. The filling consists mostly of glaciofluvial shallow braided rivers with average to low flow energy. In sedimentological terms, the deposits show significant similarity to the material of glaciofluvial kames found in the Łódź region. The authors believe there is a link between the accumulation in the tunnel valley and a particular variety of areal deglaciation, which was responsible for the formation of the fairly unvarying glacial relief. In outcrops in Łaznowska Wola, including the ones located in a hill that had been previously interpreted as an esker, some intrusive diapiric structures were documented, which reached the land surface. These folded and locally disjunctive disturbances provide evidence for deformational origin of the hill.