Warmińska prowincja paleogeograficzna plejstocenu (północno-wschodnia Polska)

Abstract

The Warmia Palaeogeographic Province of the Pleistocene (north–eastern Poland).S u m m a r y. The historic area of Warmia (western part of NE Poland) can be considered as a separate geological unit. In particular it applies to its Pleistocene sedimentary complex with a very limited occurrence of morainic deposits, commonly forming discontinuous horizons. Intermorainic deposits predominate, including mainly ice-dam lake deposits which occur at different levels. The sub-Pleistocene relief variations reach up to 400 m, with glaciotectonic upthrustings of Neogene deposits extending to the topographic surface. The province area coincides with theWarmia ice-sheet lobe of the last glaciation (Main Stadial of the Vistulian Glaciation). The eastern boundary of the area is represented by an interlobe zone coincident with the western slope of the Mazury–Suwałki Anteclise. The boundary is a tectonic discontinuity zone extending down to the crystalline basement. The eastern, anteclise area was stable during the Pleistocene, while the area of Warmia (Peri-Baltic Syneclise) was unstable mainly due to cyclic ice-sheet loads which resulted in subsidence in theWarmia region. It, in turn, caused a bending of the ice sheet body, movement acceleration and a change in ice flow direction in Warmia. During interglacials, relaxation uplifting movements triggered stronger erosional processes. These movements were dependent on surface relief, stimulating the formation of deeply rooted glaciotectonic structures.