Glacial Processes and Ice Movement
- Created by: roror
- Created on: 18-05-18 10:16
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- Glacial Processes and Ice Movement
- Erosion
- Plucking
- Glacier freezes onto rocky outcrops, and pulls away rock as glacier moves away
- Mostly occurs at glacier base, where pressure causes melting-which will refreeze and attach to rock
- Leaves a jagged surface
- Abrasion
- Material that's transported, it rubs against the valley floor and sides
- Coarse materials cause striations, fine sediments polish
- Nivation
- Series of processes (freeze thaw,chemical weathering) that operate under a layer of snow
- Nivation hollows occur when there's the accumulation of more debris by repeating seasons of freeze and thaw with moresnow
- Form beginning of a corrie
- Plucking
- Transportation
- Sub-glacial
- Base of glacier
- En-glacial
- Within glacier
- Supra-glacial
- Ontop of glacier
- Sub-glacial
- Depostion
- Till- unsorted, released by meting ice
- Angular depsoits
- Ice Movement
- Accumulation makes them move due to gravity
- Moves like plastic under pressure
- Will shatter if put under immediate tension
- Moves like plastic under pressure
- Lower zone has meltwater due to pressure
- Moves like plastic under pressure
- Will shatter if put under immediate tension
- Moves like plastic under pressure
- Internal Deformation
- Stress builds up, often when an obstacle is met
- Ice crystals orientate themselves in direction of ice movement and slide past each other
- Mostly cold based
- Rotational Flow
- In corrie, when ice moving downhill pivots around a point
- Compressional Flow
- When there's a reduction in gradient of valley floor
- Decceleration and thickerice
- Lots of erosion
- Basal Sliding
- Meltwater acts as a lubricant, speeding iceflow
- Extensional Flow
- Valley is steep,ice accelerates and ice is thinner
- Lots of crevasses
- Valley is steep,ice accelerates and ice is thinner
- Surges
- Rapid,sudden movements due to excessive build-up of meltwater
- Accumulation makes them move due to gravity
- Erosion
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