Pedogeomorphology of Semiarid Soils of Ulu Peninsula, James Ross Island, Antarctica

Abstract Located in a transitional climatic zone of the Antarctic continent, James Ross Island (JRI) presents soils that reflect complex interactions between lithology, topography, and pedogenesis. This study characterizes soils along a toposequence to evaluate how slope position and parent material control soil properties and weathering patterns in a semiarid Antarctic setting. Five soil profiles were analyzed and classified according to the World Reference Base and Soil Taxonomy systems: three on volcanic tuffs ( Terrapin Hill Fm .) and two on sedimentary rocks ( Whisky Bay Fm .). Soils were classified. To characterize and compare their properties, physical, chemical, mineralogical, and geochemical analyses were performed, including the application of weathering indices. Four profiles (three on Terrapin Hill Fm . and one on Whisky Bay Fm .) were identified as Cryosols and one as a Regosol. Chemically, all soils exhibited alkaline pH (>7.6) and elevated sodium concentrations (1195.2–4093.0 mg kg − 1 ). Results indicate that soils on volcanic tuffs show evidence of possible dry permafrost, a feature not previously reported on JRI, whereas soils on sedimentary rocks exhibit higher quartz content and more advanced weathering signatures. Sodium enrichment from marine aerosols is widespread, and weathering indices highlight clay enrichment driven by sodium and calcium. These findings advance the understanding of soil–landscape evolution in transitional Antarctic environments and underscore the role of microtopography and lithology in shaping pedogenic pathways, with implications for permafrost vulnerability and pedogeomorphic modeling under climate change, particularly by identifying soil–landscape controls on thaw sensitivity and sediment distribution patterns.