chapter  Chapter 9
14 Pages

Lithology and transport distance of glaciofluvial material

WithMarianne Lilliesköld

Research into the lithology and transport distance of glaciofluvially derived material has a long tradition. The origin of glaciofluvial material is either the bedrock, till or englacial debris. Sediments transported by glacial meltwater are deposited principally under conditions of diminishing or recessional flow. The mode of deposition controls the lithology, the stratigraphy and the facies assemblages. The lithological variation in different beds usually reflects the grain-size distribution within the internal structures, though there is some indication of differences in bedrock content between separate beds within the same size fraction. The concept of grain shape covers a combination of three elements: shape, roundness and sphericity. Boulders and cobbles are taken out from the section wall and the bedrock lithology is determined in the field. The transport distances of glaciofluvial material can be determined by choosing lithological tracers which are easy to recognize, even in finer grain sizes.