Salt-affected soils in the Lopez de Bertodano Formation, polar semi-desert of Seymour Island, Antarctica: topographic or lithological controls?

Abstract

Salinization is one of the main pedogenetic processes occurring on the semiarid zone of the Weddel sea, like in Seymour Island, where salt-affected soils are widespread. This study aimed to investigate whether topography controls the distribution of salt-affected soils on Seymour Island, particularly with reference to the Lopez de Bertodano Formation. Chemical and physical results from 45 soil profiles were used, where morphometric variables were extracted. Descriptive statistical analysis, extraction of morphometric variables, cluster analysis and principal component analysis were carried out in this database. The separation of soils associated with the López de Bertodano Formation into two groups is explained by topographic atributes, and not by soil properties. Hence, the salts in soils have a geogenic origin, and despite differences in geological units, the uniform mineralogical composition of all Lopez de Bertodano Formation results in the widespread accumulation of salts in soils, influenced by the saline parent material and the semi-desert climate. Despite the lack of topographic control in the distribution of saline soils as a whole, geomorphology play a distinct role in the formation of secondary saline features, such as crusts, efflorescences, and columnar structures, or in salt composition of salts present in the soils.