Influence of glacial environment for the roundness and shape of coarse-grained sediments of terminal moraines: an example of Waldemar Glacier (NW Spitsbergen)

The aim of the study was to determineassign the influence of glacial environment on shape and roundness of coarse-grained sediments (Ppebbles ) within and in the marginal zone of Waldemar's Glacier (NW Spitsbergen) and in its marginal zone (NW Spitsbergen). The analysis of textural features was based on the indexes of shape and roundness in five fractionsal ranges (3-5 cm, 7-10 cm, 15-17 cm, 20-25 cm, 27-30 cm). According to the Sneed & Folk's ( 1958) analysis of shape and roundness there has been measured three axies of selected clasts were measured. The degree of roundness has been estimated during field research according to the Olszewski's method (1974). While analysing sediments from Waldemar's Glacier the author conducted analysis of c Changes of C40 C40 and RA indexes as well as content of cracked grains were analysed. Moreover, relationships of C40 C40/RA and MR/Cr indexes ( co-variance analysis ) have been presented on diagrams and analysed. Most of changes are visible in the shape of pebbles (cracking along the longest axis) as well as their roundness. Changes of analysed indexes C40C40 and RA are visible on short distances (250 m). It is assumed that the main modelling factor was the relief of the area but not the distance. Sediments of youngest moraines (sites 1, 2) could be classified as supraglacial as well as short subglacial transportation. These sediments are demonstrating features similar to the source sediments. Sediments from older moraines (sites 3-7) demonstrate features of those which are reshaped in supraglacial, ienglacial and subglacial environments. Genetic classification of glacial sediments had not been fully verified by conducted analysies of relationship MR/Cr diagrams. Sediments from site 2 bad been classified as basal till even though their textural features are suggesting supraglacial transport. Sediments from sites 1-6 and partly 7 have been classified as sediments influenced by slope and weathering processes, which is related with passive transport or that active transport occurred in a short distance and grains have not been influenced by subglacial environment