PERMAFROST E FORME PERIGLACIALI NELLE NORTHERN FOOTHILLS (BAIA TERRANOVA, TERRA VITTORIA SETTENTRIONALE, ANTARTIDE)

Abstract

Permafrost and frozen phenomena of the Northern Foothills (Terranova Bay, Northern Victoria Land, Antarctica) - Permafrost-related
landforms in the Terra Nova Bay territory are mainly polygons, frost fissures, and injection cones. The polygons developed on Younger
Drift are characterized by gravelly-sandy filling while those affecting Older Drift show the occurrence of ice wedges and veins. Thermal
contraction responsible for the genesis of both landforms shows to be active at present. Injection cones are commonly associated to
perennially frozen lakes. They are interpreted as landforms due to the injection of water into the permafrost as it happens for the genesis of pingos and seasonal icings in the Arctic. A relevant role in the morphodynamic context of the area is that plaid by the high number of freezing/thawing cycles in the ground. However, frost shattering is not widespread and even frost-wedging in the bedrock is only restricted to the expansion of the pre-existing natural discontinuities.