Buried soil beneath an atsanguar stone enclosure records a former upward shift of subalpine conditions

Soils sealed beneath archaeological stone structures can preserve properties inherited from past pedogenic environments, though parent material heterogeneity and post-burial diagenesis complicate palaeoenvironmental interpretation. This study investigates a dry-stone atsanguar enclosure near Lake Verkhniy Kardyvach, Western Caucasus (∼2470 m a.s.l.), within the modern alpine belt. Regional parallels date such structures broadly to the 6th–10th centuries CE, constraining the timing of burial rather than prior pedogenesis. The buried soil was examined in three exposures spaced 15 to 20 m apart along the wall and compared against the adjacent modern alpine soil on the same mapped gabbro-diorite substrate, a secondary alpine reference profile, and lower-belt subalpine meadow and forest analogues. All three exposures showed enrichment in exchangeable Ca and Mg relative to the adjacent modern alpine soil. Manganese reached 431.5 mg kg −1 against 99.0 in that soil, while remaining well below lower-belt values. Comparable concentrations of K, Rb, Sr, Ba, Al and rare earth elements between the buried and adjacent modern upper horizons indicate that these contrasts are not produced by a gross difference in parent material. Humus and available nutrients did not reproduce the lower-belt pattern, and base saturation is treated as a derived property rather than an independent vegetation proxy. The convergent behaviour of exchangeable cations and manganese indicates an inherited pedogenic signature characteristic of a subalpine rather than alpine environment, modified after burial. Warmer conditions most plausibly extended subalpine-like pedogenesis to the present alpine shelf, though resolving the magnitude and timing of this shift requires direct numerical dating.