Micromorphological structure of maritime antarctic cryosols (King-George and Livingston Islands, West Antarctica)

Abstract

Cryosols of the Antarctic maritime area are much different from the continental ones. The relatively moderate climate conditions in Maritime Antarctica and a strong interaction between the biotic and abiotic environment are drivers for more intensive soil formation processes than in the continental regions. Soil formation studies from the Maritime Antarctica are, however, rather rare. Therefore, micromorphological investigations on polar soils can contribute to more comprehensive information on soil genesis in Antarctica. In this study, we applied the micromorphological study of thin sections from soil micromonoliths to assess the intensity and trends of the pedogenic processes in selected soils from two adjacent islands of the South-Shetland archipelago: King George Island and Livingston Island. The results obtained show that regional lithology and the origin of the incoming organic matter mainly determine the micromorphological structure of the local soils. Soil matrix micromorphological properties and features (mineralogical content, weathering stage and even partly grain-size distribution) are mainly defined by pyroclastic particles due to recent and ancient volcanic eruptions. The presence of rounded grains and aggregated mineral particles is the evidence of marine origin of the sediments. Ornithogenic soils show the clear evidence of the organic plasma formation and mineral particles aggregation via the zoogenic organic substances provided by penguins which is a unique specifics of the maritime Antarctic soils.