Rounding degree analysis

The degree of rounding analysis examines the degree of rounding of rock components in loose material such as rubble , gravel or gravel . In the case of natural sediments , the average degree of rounding is an important indicator of the type and medium of their original transport.

The rounding of a sufficient number (usually 100) of stones lying directly next to one another is determined. For this purpose, either the radius of the curvature is measured on each stone and calculated in relation to the length as a rounding index (indice d'emousse) or its degree of rounding is determined according to defined degree of rounding classes.

The determination of rounding classes has established itself in investigations in the field. Here z. B. the classes "angular", "rounded edges", "rounded" and "very rounded" are determined according to comparison tables and their proportion in the respective sediment is calculated. This means that sediments can be clearly transported as weathering debris, periglacial solifluction debris , through glaciers (glacial) or in melt water (fluvioglacial), identified as river gravel or as marine coastal sediments.

literature

• Günther Reichelt : About ballast shapes and degree of roundness analysis as a field method. In: Petermanns Geographische Mitteilungen . Vol. 105, Gotha 1961, pp. 15-24.