BUDOWA GEOLOGICZNA I MORFOGENEZA WZNIESIENIA ELBLĄSKIEGO W ŚWIETLE ZRÓŻNICOWANEJ DYNAMIKI LĄDOLODU ZLODOWACENIA WISŁY

Abstract

GEOLOGICAL STRUCTURE AND MORPHOGENESIS OF THE ELBLĄG ELEVATION IN THE LIGHT OF DIVERSIFIED DYNAMICS OF the VISTULian ICE SHEETAbstract. Glaciotectonic and neotectonic processes are among the key factors influencing the geological structure of the Elbląg Elevation. The former is undoubtedly interrelated with the latter. Intensity and scale of glaciotectonic processes were for the first time examined from the point of view of transgression dynamics of the Vistulian continental glaciers, advancing from the Baltic Sea area. Geological structure, morphology and bathymetry of the eastern part of the Central Baltic Sea bottom show that main elements of the dynamics were shaped in this area. The diversified dynamics resulted in the formation of ice streams, carrying the major part of ice mass out of the ice sheet. It also caused that the advance of the ice sheet over the Polish Lowlands was not synchronous and occurred with various intensity. The Elbląg Elevation was subjected to these rules, because it was the first to be situated within the diverse force of interaction field with ice stream B3 (streams according to Punkari, 1997), advancing towards the Polish Lowlands from the area of a submeridional megadepression of the Gotland Deep and the Gdańsk Deep (south-eastern part of Central Baltic Sea). As regards the Elbląg Elevation area, an evaluation of the scale and intensity of glaciotectonic processes in time has been performed. Especially strong glaciotectonic disturbances, appearing on the western slope of this elevation, have been related to the presence of the distinct, submeridionally oriented fault zone Iława–Elbląg (its northern part), which coincides with the western boundary of this elevation. The likely reason for the development of glaciotectonic deformation during the middle and upper parts of the Vistula Glaciation might habve been the change of the regime of neotectonic stress field, operating within the broad foreland of the Kuyavian-Pomeranian Swell, which probably took place at the end of the Eemian Interglacial.