Micromorphological difference between glacial and glaciofluvial quartz grain, evidence from Svalbard

NASA Astrophysics Data System (ADS)

Krbcová, Klára

2017-04-01

Micromorphology of glaciofluvial sediments were only partially shown by Mahaney et al. (2001). This paper deals with the main diagnostic textures of glaciofluvial sediments and changes of their micromorphology caused fluvial transport. All samples were collected in Svalbard in August 2012. Two glacial samples and six glaciofluvial samples were taken near the glacier Bertilbreen and one glacial sample and seven glaciofluvial samples were taken near the glacier Hørbyebreen. Samples were prepared according to the Mahaney (2002) and examined under electron microscope. The correlation analyses was used to set the main glaciofluvial microtextures. Similarity of the samples was tested by one-way ANOVA by F-test. Increasing numbers of V-shaped pits, rounded grains, meandering ridges and microblocks are typical for characteristic microtextures of glaciofluvial grains which had greater rate of fluvial transport. But the grains mainly transported by glacier had a greater percentage occurence of subangular grains, straight steps, straight and curved grooves, adhering particles, pitting and V-shaped etch pits. The fastest change in variability was set during the first kilometre of fluvial transport. The study was funded by the Grant Agency of Charles University (GAUK 1314214). Keywords: exoscopy, quartz grains micromorphology, glaciofluvial sediments References: MAHANEY, W. C. (2002): Atlas of sand grain surface textures and applications. Oxford University Press, USA, 237 s. MAHANEY, W. C., STEWART A., KALM, V. (2001): Quantification of SEM microtextures useful in sedimentary environmental discrimination. Boreas, 30, s. 165 - 171.