A case for chemical weathering in soils of Hurd Peninsula, Livingston Island, South Shetland Islands, Antarctica

- Significant chemical weathering occurring in soils of Hurd Peninsula
- Tephra, deposited by volcanic activity, breaks down quickly, increasing soil pH.
- High levels of organic acids on ornithogenic beaches will dissolve surrounding silicates.
- Phosphate dissolution of silicates not significant due to environmental factors
- Weatherable minerals in tephra contribute to soil development during dissolution.

The soils of the South Shetland Islands, Antarctica are considered weakly developed. Chemical weathering processes are generally considered to be negligible except in areas that receive large additions of seabird guano. In this paper we describe and analyze 19 soils on Hurd Peninsula, Livingston Island in the South Shetland Island Archipelago. The soils were classified according to US Soil Taxonomy and were generally weakly developed Gelorthents, Humigelepts and Haplorthels. However, B horizon formation, rubification and increases in extractable Fe and Al were observed on toposequences of raised beaches. The deposition of tephra and/or guano is likely responsible for the chemically driven processes. Guano deposits contain phosphates and oxalic acid, causing phosphatization and/or dissolution of silicates. Input of tephra with easily weatherable minerals may account for metastable mineral formation. Tephra deposition in the oldest raised beaches has formed a fine-textured mantle overlying the coarser textured subsoils. Highly weatherable tephra, as opposed to guano deposition, appears to influence soil formation at Hurd Peninsula.