Inventory of deformational structures as a tool for unravelling the Quaternary geology of glaciated areas

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Abstract
Glaciated areas often show strongly deformed deposits which are difficult to correlate. It may he possible, however, to analyse the relative frequency and nature of sedimentary and glacitectonic deformations in isolated exposures. Their comparison may provide a differentiation of stratigraphic and structural units with identical properties. Such an analysis has been carried out in a small Polish area (the Jaroszów Zone) where the Quaternary and part of the Tertiary sediments show a chaotic character, due to a variety of deformational processes. Deformations took place syndepositionally, metadepositionally and postdepositionally. It appears that the deformation was more or less continuous, but nevertheless some stages with more intensive deformational activity occurred. This resulted in two levels (called structural floors) that represent intervals in which the main type of deformation changed: the lowermost sedimentary unit is characterized by glacitectonic and glacidynamic structures, the middle unit by largescale load casts and associated structures, whereas the top part shows a high frequency of smallscale syn‐ and metasedimentary deformations. This analysis enabled the unravelling of the sedimentary and deformational history of the area; a similar approach might be applicable to other Quaternary areas that have been strongly deformed as a result of glaciations.