Podzolised soils developed from slope deposits reveal relict frost features concealed by organic matter accumulation in the Stolowe Mountains (SW Poland)

Considering the comprehensive morphology and genesis of Podzols of the Stolowe Mountains, and the still-possible impact of frost actions and other processes related to cold climate on these soils, the main aims of this study were to determine whether (i) the heterogeneous Podzols in the Stolowe Mountains underwent a phase of development in a cold climate, resulting in frost action features visible on the micromorphological level, and whether (ii) contemporary cryopedogenic traces are masked by the translocation of organic matter due to the podzolisation process. Four soil profiles were investigated, revealing distinct layers corresponding to different periods of soil formation. Under field observation, no explicit frost-related characteristics were observed. Nevertheless, micromorphological analysis revealed cappings of fine materials on grains or peds, as well as development of granostriated (or any striated) b-fabric that resulted from the alternating effects of thawing and freezing processes. Moreover, micromorphological analysis revealed the presence of microstructures that could be the result of cryogenic processes, such as platy, angular blocky and lenticular features, as well as plane, vugh and star-shaped void types. The translocation of organic matter during podzolisation modified or concealed the frost-related features that developed during the late Pleistocene and early Holocene. This is evident, for instance, in the accumulation of organic matter on cappings and within soil voids, which further hinders the identification of frost-related characteristics and the interpretation of the soil's evolution. Macromorphological observations enhanced with micromorphological analyses revealed three distinct layers: (i) a young upper layer composed of loose, sandy material; (ii) a deeper layer containing a spodic horizon with frost actions, involving pedofeatures associated with the Pleistocene cold climate and (iii) a deeper subsoil basal layer. The abovementioned microstructures, combined with lithological discontinuity, support the hypothesised polygenetic origin of Podzols in the studied region.