Fan sediments as indicator of gully erosion sta ges on the example of the Suwałki Lakeland (NE Poland)

Study of sediments at gullies mouths conducted in the Suwałki Lakeland (NE Poland) showed that fan sediments are significantly diversified. The changes of sediment type could be linked to forest clearance and farmland expansion. Dating and lithological properties of fan sediments allowed to determine the stages of gully erosion. The research also included studies of sediments accumulated within last 200 years in 6 small gully catchments of different degree of cultivation. Supply of the sediments derived from soil erosion to the gully fans was very limited in catchments where only 15% of the land was cultivated. This process was intensively active in catchments where cultivated land occupied 77% of the area