Ice-flow dynamics and meteorite collection in Antarctica.

Typical targets for meteorite search in the ice-sheet covering Antarctica are blue ice fields in front of major bedrock obstacles, where the meteorite-bearing ice slows down, is uplifted and exhumed by ablation. However, in some areas collection occurs in the lee of topographic barriers, as documented in the downstream side of the Frontier Mountain, a major emerged bedrock barrier. In this study we present an analogue modelling study of ice flow at Frontier Mountain, which has been chosen as example study area because an exceptionally complete set of glaciological data is available to investigate the causes leading to meteorite concentration. Results of modelling show how the boundary conditions (mainly the bedrock topography) control ice flow and how this flow, coupled to high ablation, may give rise to a stable meteorite trap downstream of major topographic obstacles. Modelling results support the contention that, as erosion is not a mountain builder, ablation does not represent a driving force in ice flow dynamics, although it plays a significant role in shaving stranding surfaces and exhuming meteorites.