Bag bottom
The pocket floor is a relief shape of the floor ( frost pattern floor ) characterized by cryoturbation (movements of the floor near the surface due to freezing and thawing ). When the material is displaced in the thawing zone, the existing horizons and layers are irregularly turned into pockets due to bending and sprains . Fine-grained layers sink into mostly coarse-grained layers. Pocket bottoms occur due to the climate and depending on the soil structure and soil moisture with different intensities at depths of up to several meters.
In geology, similar Pleistocene phenomena are also referred to as Würgeboden, Brodelboden or teardrop soils.