Environmental Conditions in the Late Pleistocene at the Southern Margin of the European Periglacial Domain (Hungary) Inferred From Quartz Grain Microtextures

The paper investigates environmental conditions prevailing at the southern margin of the European periglacial domain in NW Hungary (Kemeneshát area) during the Late Pleistocene. Samples of sediments infilling sand wedges and their host sediments were analyzed by examining the grain‐size distributions, as well as the morphology and microtextural characteristics of sand (250–500 μm) quartz grains. The surface microtextural characteristics of 460 quartz grains were analyzed with a scanning electron microscope to infer the sedimentary processes that affected the analyzed sediments. The number of frost‐induced microtextures was also determined for the sand wedge infillings. Statistical analyses, including hierarchical clustering and principal component analysis, successfully differentiate sediments infilling sand wedges and their host sediments based on the frequency of occurrence of microtextures observed on the surface of quartz grains. The morphoscopy and surface microtexture of the grains indicate that the host sediments (n = 160) originate from subaqueous (lacustrine, fluvial) environments, as they are characterized by smooth and glossy surfaces and V‐shaped percussion cracks. In contrast, the sand wedge infilling grains (n = 300) were weakly abraded in an eolian environment, as inferred from rough surfaces and rounded edges. The number of frost‐induced microtextures (freshly developed conchoidal fractures and breakage blocks) suggests an initial stage of frost weathering. The value of the frost action index calculated for these sediments supports the hypothesis of the presence of (at least discontinuous) permafrost in the study area. The obtained results contribute to the understanding of the paleoenvironmental dynamics of the Pannonian Basin during the last stages of the development of the studied sand wedges.