MIKRORZEŹBA POWIERZCHNI ZIAREN KWARCOWYCH FRAKCJI PIASZCZYSTEJ OSADÓW PREGLACJALNYCH SERII KOZIENICKIEJ JAKO WSKAŹNIK WARUNKÓW TRANSPORTU I DEPOZYCJI W POŁUDNIOWEJ CZĘŚCI NIZINY MAZOWIECKIEJ

Abstract

MICROMORPHOLOGY OF SAND QUARTZ GRAINS FROM THE PREGLACIAL KOZIENICE SERIES AS AN INDICATOR OF TRANSPORTATION AND DEPOSITION PROCESSES IN THE SOUTHERN MAZOVIAN LOWLANDAbstract. Surface micromorphology of quartz sand grains (0.8–1.0 mm) of preglacial sediments from the Mazovian Lowland (Poland) was analysed under scanning electron microscopy (SEM) in order to determine characteristic features of source material, and conditions of transport and deposition of the sediments. Samples were taken from the Stanisławice, Brzóza, Januszno and Mościska sites. Research results show that all the analysed grains represent a high-energy aqueous environment, irrespective of location and facies setting. The most characteristic features of the preglacial sediments is a very poor grain rounding, equal in all cases. Chemical etching progressing during transportation of the sediments was a dominant process shaping the micromorphology of the grains. This process led to development of a shiny, smooth grainsurface called „dulled surface”. Mechanical abrasion played only a secondary role. Most probably, the preglacial deposits sourced from weathered sediments which had apparently identical features as the analysed sediments. They were transported most probably over a very short distance.