EN
The gullies in the Suwałki Lakeland are located very unevenly. The density of gully network is 0.2 km/km² on average and locally reaches 0,5- 1, 2 km/km². The incisions are located on slopes of tunnel valleys and wide depressions, particularly in the vicinity of met-outs and lakes. These slopes have heights of over 30 m and lengths of over 100 m and are composed of sandy and gravel, sandy silt and sandy till diamictons. The gullies are mostly simple landforms and only sporadically create small dendritic systems. Considering morphology and size of the incisions, two kinds of gullies can be distinguished. The larger gullies are developed along dellies (bowl-shaped, dry valleys) or melt-out valleys. The smaller and shorter gullies occur on the slopes of melt-out depressions and tunnel valleys. Ages of peat covered by fans at the mouths of larger gullies indicate that gully erosion started between 3520±70 to 2240± 100 BP. Two different units build the fans and infilled the gullies. The older unit contains sand and gravel that originated from the bottom and bank erosion of the gullies and resembles alluvium. The younger unit consists of colluvium. The fans at the mouths of smaller and shorter gullies are mainly built of colluvium. The analysed sediments have different characteristics, which indicate that the source material and depositional changes are linked to forest clearance and farmland expansion starting in the 7th century AD and continuing in the Middle Ages.