Diversity of soils on Kolguev Island with cryometamorphic horizons

Kolguev Island (Barentz Sea, the subzone of typical tundra) was poorly soil surveyed until recently. During expeditionary research 2018–2023, it was revealed that a significant proportion of the soil cover is represented by soils that have horizons with a well-manifested structure, which were diagnosed as cryometamorphic ones. In this regard, the purpose of this work is to characterize the diversity and morphological features of tundra soils with a cryometamorphic horizon identified on the island. The cryometamorphic horizons most often had the specific angular-grainy structure with sharp edges or granular structure with rounded surfaces. The most typical size of aggregates is 1–3 mm; less common – up to 4 mm or less than 1 mm. In some cases, the structure was water-resistant and the soil aggregates had a denser, drier interior. A platy-grained structure with silty-sand coatings was less common. A key feature of the cryometamorphic Kolguev soils is lacking structure in the upper 5–10 cm of the profile. Such soils are the main component of the soil cover. The gleyic subtype of cryometamorphic soils and cryometamorphic gleezems are more often found as components of the soil cover micropatterns. Cryometamorphic soils with a morphologically pronounced spodic horizon were described in one of the central parts of the island. Based on the principles of Soil Classification of Russia, the following types of soils were identified: cryometamorphic, mucky-cryometamorphic, cryometamorphic gleezems; as well as soils, that were tentatively classified as a new type – cryometamorphic podburs and a new subtype – cryometamorphic peaty gleezems. Thus, the study of Kolguev soils showed that the cryometamorphic soils are distributed much extensive than previously assumed.