ASGP (2008), vol. 78: 19-35

TILL BASE DEFORMATION AND FABRIC VARIATION IN LOWER ROGOWIEC (WARTANIAN, YOUNGER SAALIAN) TILL, BEŁCHATÓW OUTCROP, CENTRAL POLAND

Peter ALLEN (1) & Dariusz KRZYSZKOWSKI (2)

1) 113, Churchgate, Cheshunt, Herts, EN8 9NB, England
2) Institute of Geological Sciences, University of Wrocław, Cybulskiego 30, 50-205 Wrocław, Poland; e-mail: dariusz.krzyszkowski at ing.uni.wroc.pl

Allen, P. & Krzyszkowski, D., 2008. Till base deformation and fabric variation in Lower Rogowiec (Wartanian, younger Saalian) Till, Bełchatów outcrop, central Poland. Annales Societatis Geologorum Poloniae, 78: 19-35.

Abstract: We documented that the Wartanian (younger Saalian) Lower Rogowiec Till exposed at Bełchatów, central Poland, is not sedimentologically or structurally homogeneous, and suggested that the till macrofabric patterns and deformation structures may be related to stress conditions in the glacier at the time of deposition. The distribution of deformation structures below and within the till forms a pattern, most probably associated with compressive flow and/or with stronger stress reaction, creating stronger fabrics, above clay beds due to high pore water pressure. The intervening areas, lacking deformation structures, occur between the zones of compression, where pressure would have been less. These patterns occur in a repeated sequence along the sections, which suggests that there may be a control, such as basal glacier stress conditions. The sites showing deformation occur about every 10–20 m. This could imply that the zones of shearing at the ice front have a similar spacing. There are no features in the pattern of the till macrofabrics and deformation structures to suggest that the local Kleszczów Graben or a pre-existing valley had any effect on the mode of till deposition.