Pleistocene loess deposits and mollusc assemblages in the Eastern Pre-Alps

Abstract

In comparison to other areas in low mountain regions, the widespread occurrence and thickness of loess is impressive in the northern Vienna Forest. Due to differences in grain size, it is obvious that the loess deposits of the Hagenbach Valley deviate from those of other locations. In comparison to the results of Krems and Stillfried, the loess of the Hagenbach Valley has a pronounced maximum in the sand fraction reflecting an essential influence of the Flysch sandstone and a proximity to the source sarea. The loess of the Hagenbach Valley is specified as sediment with significant local impact due to a remarkable influence of short distance transport. Partly, the loess is of alluvial origin as it contains small pebbles and therefore it reflects cool and wet paleoenvironmental conditions. The malacological evidences coincide with the geomorphodynamic conditions. Redeposition processes cause a generally high degree of fragmentation. The malacological analyses proved 28 species of terrestrial gastropoda, with a total number of 3,283 specimens. The results indicate very humid and cool climate and a weakly expressed, slightly more favorable period is visible in one of the horizons. Copyright: