Deglacjacja lobu Widawki

Abstract

DEGLACIATION OF THE INLAND ICE OF THE WIDAWKA LOBESummaryThe paper deals with he deglaciation of the inland ice of the Masovian-Podlasie Stage (Middle Polish Glaciation). Within the Widawka River basin, the continental glacier extended, with its vast lobe (called in this paper the Widawka lobe), far south of Lódź, reaching the area of Radomsko.Here, three zones of deglaciation have been distinguished: ­– zone of frontal recession comprising 5 end moraine lines, hills of crevasse accumulation, and marginal and drainage valleys. For the most part, the end moraines are of recession character, however, traces of inland ice transgresssion are known to occur in the moraine lines II and V;– zone of crevasse cracking of the inland ice, characterized by the occurence of channel valleys, eskers and numerous hills of crevasse accumulation. As a result of areal deglaciation, plains of boulder clay have been formed;­ – zone of block desintegration of the continental glacier, comprising 3 complexes of irregularly distributed hills referred to fluvioglacial kames. The kames are built up of sands with gravel admixture. The limno-glacial kames consist, too, of silt and of fine-grained sand. In this zone also forms of areal deglaciation occur, i.e. plains of boulder clays and melting bowls left behind by ice blocks.On the basis of morphological axes of certain relief forms, on extension of glacitectonic structures, and on spread of local Mesozoic rocks, directions of both transgression arid transportation of the continental glacier have been ascertained to run from NW to SE, and in the western part, from N to S.The main features of the relief in the zone distinguished were conditioned by a differentiation of the processes that took place before, still in the living glacier. An almost common fluviaglacial character of the accumulation of end moraines has been ascertained to occur in the marginal area of the Widawka lobe, particularly in the internal moraine lines.The extent of the inland ice of the Widawka lobe, generally, however, that of the Masovion-Podlasie Stage, stresses the influnece of large structural elements of the Mesozoic substratum. Small structural elements have influenced, in turn, the formation and the position of channel valleys and eskers.