Formation of Vesicular Pores in Aggregates from the Eluvial Horizon of Albic Glossic Retisol during Freeze-Thaw Cycles

In this article, we discuss the contribution of capillary wetting and multiple freezing and thawing to the formation and evolution of vesicular micro– and mesoporosity in an aggregate of 3 mm in diameter from the eluvial horizon of soddy–podzolic soil (Albic Glossic Retisol (Loamic, Cutanic)). The main visible changes occur during capillary wetting and the first four cycles of freezing and thawing. Capillary wetting of the air-dry aggregate initiates the formation of vesicular micropores in the soil mass. The first freezing fixates the newly formed vesicles and contributes to the development of microschlieren in the aggregate. The first thawing causes the isolation and growth of individual vesicular pores. In the subsequent three freeze–thaw cycles, freezing fixates the vesicular pore space pattern, whereas thawing promotes the coalescence of small vesicular pores into larger vesicular pores. During the fifth and next cycles, many large vesicular pores leave the deformed aggregates aggregate, so that horizontally oriented cryogenic microschlieren tend to predominate in the frozen aggregate after 10–20 freeze–thaw cycles.