Aufeis
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Aufeis (German for "ice on top") is new ice that continues to form on top of older ice.
[edit] Description
Aufeis accumulates during winter along stream and river valleys in arctic and subarctic environments. Aufeis forms by upwelling of river water behind ice dams, or by ground-water discharge. The latter mechanism prevails in high-gradient alpine streams as they freeze solid.
Ground-water discharge is blocked by ice, perturbing the steady-state condition, and causing a small incremental rise in the local water table until discharge occurs along the bank at the top of the previously formed ice.
During winter, successive freezing of the onlapping ice layers can lead to aufeis accumulations several meters thick.
[edit] References
- Wanty et al, Aufeis Accumulations in Stream Bottoms in Arctic and Subarctic Environments as an Indicator of Geologic Structure
