Reconstruction of subglacial depositional conditions based on the anisotropy of magnetic susceptibility: an example from Dębe (central Poland)

Abstract

ABSTRACTThe analysis of low‐field anisotropy of magnetic susceptibility (AMS) was used to reconstruct the subglacial deposition conditions during the Main Stadial of the Odranian Glaciation (MIS 6) in till deposits from a site in Dębe (central Poland). Based on the AMS parameters, six till beds were identified (intervals 1–6). The declination of the maximum magnetic susceptibility axis (k1) indicates that the ice sheet was moving in from the northwest. The obtained results confirm the thesis about the preferred direction of ice‐sheet transgression during the Odranian Glaciation (MIS 6) in this part of Poland. This interpretation is also confirmed by data obtained from measurements of the long axis of clasts, which agree with the orientation of k1. Based on the AMS results, a significant part of the profile was deformed through simple shear and direct interaction of the ice sheet with the underlying sediment (beds 2–5). The lowest part of the till (bed 6) may have been deposited on a southeast‐trending slope or post‐depositional deformed by uneven loading of the ice cover. The upper part of the profile (especially in interval 1) could be deposited with an impact of pore water.