Uncovering the relict periglacial landscapes of the central Chile Andes: Soil formation and polar desert features at 33°S

This study investigates periglacial relict surfaces in the central Chile Andes (33°S), focusing on soil formation and geomorphic features. These surfaces, preserved since preglacial periods, provide a unique record of long-term landscape evolution. We analyzed 12 sites with a mean elevation of ∼3200 m a.s.l., spanning 2200–4200 m, with periglacial and polar desert features appearing predominantly above ∼3300 m a.s.l. Fieldwork involved describing and sampling soil profiles, characterizing physical and chemical properties, and documenting geomorphic features across the altitudinal transect. Our results highlight desert pavements, vesicular horizons, patterned ground, and ice wedges, features indicative of a distinctive high-altitude periglacial dominated climatic regime. Soil formation trends across altitudinal vegetational belts show the development of mollic and argillic horizons, shaped by prolonged aridity and minimal glacial erosion, suggesting they are pre-Quaternary surfaces. In-situ mechanical weathering appears central to the genesis of pavements and vesicular horizons. The presence of these features at high elevations, together with evidence of periglacial processes, underscores the distinctive environmental conditions of the high elevation central Chilean Andes. Despite precipitation exceeding ∼500 mm y⁻¹ -higher than in Antarctica or the Arctic-the soils display features typical of polar deserts sensu lato. These findings provide insights into the long-term climatic evolution of mid-latitude high-altitude environments, offering a new perspective on the region's climatic history and the formation of polar desert-like features in a non-polar setting. More broadly, they highlight the significance of mid-latitude high-altitude environments for interpreting polar desert-like features outside polar regions.