Periglacial processes and landforms in the South Shetland Islands (northern Antarctic Peninsula region)

Abstract

Periglacial processes and landforms together with the presence of permafrost are among the most relevant geomorphological elements in the northern Antarctic Peninsula region. Their distribution affects the hydrology and has consequences for the ecosystems of the ice-free areas. In this paper a compilation of the different types of periglacial landforms and processes occurring in the South Shetland Islands is carried out and their spatial distribution is analysed. Furthermore, the relationships of the periglacial landforms with local conditions and permafrost distribution have been taken into account. A total of thirty three types of periglacial landforms were identified and considered in this work. Patterned ground and stone fields are the most common periglacial landforms, which are located within a wide altitudinal range and mainly on platforms. Field studies, aerial photograph and satellite imagery interpretation were implemented to produce detailed maps from ten areas with different geological, geomorphological and relief characteristics, including the largest and most relevant ice-free areas within the archipelago, showing the presence and spatial distribution of periglacial landforms. This work shows that the periglacial environment, primarily conditioned by the regional climatic conditions, has a great diversity in the studied region and that the distribution of the periglacial landforms is also related to local relief and geomorphological characteristics, lithology, hydrogeology, and presence of permafrost where altitude plays an important role. Periglacial phenomena are widespread above 10m a.s.l. and are especially active on slopes and platforms between 30 and 100m a.s.l. The spatial distribution of periglacial landforms helps to identify the presence of permafrost that is dominant above 25–30m a.s.l. and more than 70% of the surface is occupied by active layer-related landforms.