Morphology of eskers in Poland, southward of the Last Glacial Maximum
Małgorzata Frydrych
Abstract
The article presents the results of morphometric analysis of approximately 300 eskers in Poland, to the south of the Last Glacial Maximum. The measurements included their length, fragmentation, maximum width, elongation, sinuosity, orientation and presence of tributary ridges and their order. The analysed area of Poland is dominated with eskers of 1–3 km in length with the maximum length slightly exceeding 10 km. They are characterised by the average maximum width of 250 m, clear elongation, slight predominance of straight over sinuous forms, and the presence of tributary ridges of maximally second order. The distribution and morphological characteristics of eskers in Poland, to the south of the LGM were mainly influenced by the origination of forms on a permeable substrate in N-channels and a combination of N-channels and R-channels, complex genesis of eskers and superimposition of open crevasse sediments over the subglacial facies, as well as formation of eskers during older glaciations (MIS6-12) and their subsequent transformations and erosion under variable climatic conditions. The morphological and sedimentological features of analysed eskers support the theory of predominance of the synchronous model of esker formation in this area. The presented studies refine the understanding of eskers of older glaciations than the forms that originated within the extent of the Last Glacial Maximum. The research provides new insights into the nature of esker formation and subglacial meltwater drainage in the area of soft bed.