Geology Reference
In-Depth Information
Figure 13.11.
Map showing the limits of the last glaciation and the Pleistocene periglacial zone of
central Poland. Also shown are the locations of Gora Sw Malgozata and Walewice (see Figure 13.12,
13.13).
the base of this buried slope, a large upturned block of stratifi ed-slope sediment is, itself,
buried by non-stratifi ed slumped material.
The paleo-cryostratigraphy of the slope sediments at Walewice indicates that perma-
frost conditions were present throughout the period of time during which the terrace edge
was degraded. The block appears to have fallen in a frozen state and to have been quickly
buried because, if it had thawed, stratifi cation would not have been preserved. In all prob-
ability, the block fell when a stream laterally undercut to form a thermo-erosional niche
(see Chapters 8 and 10). Two generations of frost fi ssures are identifi ed; an older set asso-
ciated with collapse of the block and a younger set developed in material which buried
the block. They prove that permafrost was present throughout this period of slope
modifi cation.
In terms of landscape modifi cation, the slope at Walewice saw the elimination of the
terrace edge and the development of a low-angled slope with a progressive reduction in
relative relief through movement of material into the pradolina.
