Closed depressions in the European loess belt – Natural or anthropogenic origin?

© 2017 Elsevier B.V. Closed depressions (CDs) are typical geomorphological features of the loess belt in Europe. CDs have been reported in several regions of the European loess belt, where they are described as hollows, mardeles, wymoki, crovuri, bludtsa and zapadiny. The natural and anthropogenic origins of CDs are debated in literature. Moreover, no comprehensive review of the geomorphic properties or the evolution of these depressions exists. Therefore this paper reviews the characteristics of CDs in the European loess belt and attempts to better understand their genesis based on detailed case studies. The main morphometric features as well as sediment deposits within CDs in several sub-regions of Europe were analysed and compared. Morphometric properties of CDs from the West European and East European loess belt were investigated through a comparison of CDs from two representative regions, i.e. East Poland and Central Belgium. In both study areas, CDs under cropland are similar. However, a comparison of morphological features of CDs under forest, revealed clear differences, suggesting a different origin of CDs from both regions. Infilled sediments in CDs show various litho-genetical features in different regions of the European loess belt. The morphometric features, ages and stratigraphy of infillings clearly indicate that both anthropogenic and natural processes have shaped these landforms within the loess belt of Europe. CDs observed in Eastern Europe may have a very different origin than those documented in Western Europe. Detailed analysis of CDs in Poland and in neighbouring regions of East Europe, suggest that CDs are natural landforms: thermokarst, deflation and dissolution of loess are reported as probable genetic processes. In contrast, several studies in Western Europe indicate a dominant anthropogenic origin (i.e. digging of calcareous loess or marls, bomb and mining craters, collapse of underground limestone quarries), although CDs formed by natural processes (i.e. piping, dissolution of limestone and salt lenses below the loess cover) are reported as well. CDs act as important archives, allowing one to reconstruct both natural and anthropogenic processes operating in the past. As CDs store most sediments eroded within their catchment they provide ideal sediment traps to assess long-term erosion rates in these environments which have hitherto been under-researched. More research is needed to unravel the genesis and evolution of these depressions to better understand the importance of the Late Glacial and Holocene stages for the morphogenesis of the loess belt in Europe.status: publishe

Geotourism assets of loess relief in western part of the Lublin Upland

The characteristic group of loess relief in the western part of the Lublin Upland makes up a unique and varied landscape that is particularly attractive for tourists. Gullies, whose density exceeds 11 km/km2 in the Kazimierz Dolny area, are the best known element of the loess landscape. Along the gullies, tourist and interpretive trails have been established, but there is a lack of well-prepared geotourism trails. The southern part of the study area, the Urzędów Hills, is particularly underdeveloped in terms of tourism. This study presents the key characteristics of loess relief in the western part of the Lublin Upland, the current development of tourist infrastructure, and prospects for geotourism based on the unique landforms in the area. A few geotourism trails focusing on the unique loess relief features have been proposed, and attention has been drawn to threats to these landscape assets posed by certain forms of adventure tourism and problems related to private land ownership

Geological conditions of the distribution of closed depressions in the Nałęczów Plateau (Lublin Upland, E Poland): are they an origin determinant?

Closed depressions (CDs) are landforms typical for loess areas. 1761 CDs have been inventoried within the Nałęczów Plateau. Large concentrations of CDs: 30–40 forms per km2 occur in areas where thick (more than 10 m) complex of glacigenic sediments (mainly glacial tills) or clay (limniglacial) deposits underlying loess cover. Areas with a low concentration of CDs (fewer than 10 forms per km2) correspond to areas where the loess cover lies on a bedrock (opokas) or on thin sandy-gravelly deposits. The distributions of CDs depends on the conditions of Pleistocene permafrost development and melting, linked with lithological properties of the sediments under loess cover