Abstract:

In southeastern Central Europe, substantial, decametre thick loess-palaeosol sequences (LPS) can be observed. They are widespread in dry landscapes that are presently characterized by steppe and/or forest-steppe climates, forming extensive loess plateaus which are the most important sinks for aeolian dust on the Eurasian continent. Here, soils form predominantly accretionary, driven by both bioclimatic factors and wind-blown dust input contemporaneous to soil formation. This contrasts with other parts of these loess landscapes where ecosystems increasingly resemble those of Atlantic-influenced Western Europe and Holocene soils have developed on Upper Pleistocene or older loess—often under forest ecosystems with minimal input of windblown dust. These differences in recent loess landscapes of southeastern Central Europe result in regional variations in pedofacies and thus in soil type areas and their characteristic soil catenas, best preserved in loess plateaus.
Similar variations in pedofacies can be identified in Pleistocene LPS dating back at least to the Middle Pleistocene. In contrast to a spatial soil catena, these variations are the direct result of temporal climate changes at the respective sites. Here, the different soil types often formed as soil complexes (SCs) under predominantly accretionary regimes are separated not only spatially within a landscape but also temporally by phases of loess accumulation, and the resulting LPS are excellent archives of Pleistocene continental climate evolution.
Spatial variations in bioclimate and in sedimentation and erosion dynamics play a decisive role in determining what ultimately remains of a soil formation phase. Furthermore, alongside erosion, sediment-starved conditions are also observed in Holocene soil catenas as well as in lateral variations of LPS, where even merging of palaeo-SCs of different ages and splitting of same-age SC have been documented (e.g. Danube banks, Black Sea coastal cliffs). Comparable to the temperature-controlled treeline in alpine and polar regions, in recent loess landscapes of southeastern Central Europe there is also a relatively pronounced lower treeline driven by moisture conditions which marks the transition from dry steppe to lusher forest environments, which consequently also leads to spatial variation in soil formation.
Here we present conceptual ideas based on field observations and literature reviews. We assume that spatial and temporal differences, as well as similarities, in pedofacies are currently overlooked in the study of interglacial palaeo-SCs in southeastern Central Europe. Failure to recognize such pedofacies variations carries the risk of erroneous profile correlations, leading to incorrect chronostratigraphic and palaeoclimatic conclusions.