EVSC 1010 Lecture 5: Glaciers- Jan 29
15 Aug 2016
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Document Summary
Glacier: massive, long-lasting, moving mass of compacted snow & ice. Amount of glaciers varies over history b/c certain aspects of earth"s system vary changing surface temperature/solar radiation reaching planet surface (variations in orbit, variations in axis tilt, pole stars shift) Firn: rounded ice grains (buried deeper in snowpack it converts to glacial ice) Snow crystals from newly fallen snow become rounded & denser as snowpack is compressed & alternately warmed/cooled over time. Glacier types: alpine glaciers: form at high altitudes in mountains, ice sheet (continental glaciers): large glacier covering surrounding terrain. Glacier movement: (lines of poles measure movement: basal slip- entire glacier slides over bedrock, plastic flow- ice flows as viscous fluid. Zone of accumulation- region where more snow falls during winter > snow melts during summer (net accumulation of snow/ice); higher elevations. Zone of ablation- more snow melts during summer than accumulates during winter.
