Term: | Glacial polish |
Definition: |
Glacial polish is the leveling and smoothing of rock by fine-grained debris at the glacier bed. Glacier ice alone is too soft to be a powerful rock-cutting agent. Many glaciers are armed with rock fragments embedded within the ice that are effective cutting tools. The rock-choked ice grazes over the glacier bed, removign rock obstacles and leaving the bedrock rounded and smoothed. In some places fine-grained debris polishes the bedrock to a lustrous surface finish called glacial polish. Coarser rocks may gouge scratches called striations.
The abrasion of bedrock surfaces by materials carried on the bottom of a glacier. This process leaves these surfaces smooth and shiny. PhysicalGeography GCW |