Summary: | Abstract Ice streams are corridors of fast ice flow (ca. 0.8 km/year) within an ice sheet and are responsible for discharging the majority of the ice and sediment within them. Consequently, like the arteries in our body, their behaviour and stability is essential to the well being of an ice sheet. Ice streams may either be constrained by topography (topographic ice streams) or by areas of slow moving ice (pure ice streams). The latter show spatial and temporal patterns of variability that may indicate a potential for instability and are therefore of particular interest. Today, pure ice streams are largely restricted to the Siple Coast of Antarctica and these ice streams have been extensively investigated over the last 20 years. This paper provides an introduction to this substantial body of research and describes the morphology, dynamics, and temporal behaviour of these contemporary ice streams, before exploring the basal conditions that exist beneath them and the mechanisms that drive the fast flow within them. The paper concludes by reviewing the potential of ice streams as unstable elements within ice sheets that may impact on the Earth's dynamic system. D
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