Evolution of the Toruń Basin in the Late Weichselian

The Toruń Basin is the eastern fragment of the Noteć-Warta ice-marginal streamway. Genesis of the Toruń Basin firstly demonstrates processes of erosion and accumulation of meltwaters and the Vistula waters which occur on the background of changes in the height of erosion base and tectonic movements. In the formation of the Toruń Basin one cannot exclude its older, glacial and interglacial assumptions either, as through its location the form is related to the course of the fossil valleys. The article presents functional stages and reorganizational mechanisms of water discharge directions in the Toruń Basin, stimulated by the tectonic activity of the older bed. In the Toruń Basin the following terrace sets can be distinguished: a) the outwash levels formed not so far away from the ice-sheet front, i.e. during the Wąbrzeźno Subphase, b) the distal sections of the outwash (XI, X), c) the Vistula ice-marginal streamway terraces (the transitional terrace and IX), d) the Vistula ice-marginal streamway terraces (VIII-VI) from the period of this river bifurcation at Fordon, and e) lower terraces of the Vistula valley. In the upper part of the Late Weichselian waters formed a system of sandbed braided rivers with changeable flow regime, which initially had higher energy, then reduced energy and high again. This resulted from the ice-sheet front retreat, intensity of its ablation and the inflow of the Vistula waters from the south.