Periglacial Environment

Periglacial Environment

1. Cold, non-glacial environments - frost dominates

   • Mean temp. less than 3C
   • Frost dominates below -2C

2. TYPES

   • 1. DRY CLIMATES WITH SEVERE WINTERS
     • Seasonal + deep freezing
     • Presence of permafrost
   • 2. HUMID CLIMATES WITH SEVERE WINTERS
     • Irregular distribution of permafrost
   • 3. CLIMATES WITH SMALL ANNUAL TEMP. RANGE
     • Shallow and diurnal freezing (no permafrost)

3. Climatic environments

   • High Arctic - Canadian Arctic
   • Continental - Siberia
   • Alpine - Alps
   • Tibet Plateau (high alt, low lat) - Himalayas

4. Permafrost

   • Ground that is frozen for 2 consecutive years
   • Hydrology
     • Dissolved salts lower freezing point
     • Different soils retain varying amounts of unfrozen water
   • Distribution
     • 25% Earth's land surface
   • Conditions that affect permafrost
     • Relief/slope orientation
     • Rock + soils types (albedo)
     • Snow cover (insulation)
     • Vegetation (interception)
   • Landforms associated with permafrost
     • Palsa's
       • Peaty permafrost mound - alternate layers of ice + peat
       • 1-7m height
     • Pingo's
       • Mound of earth covered ice
       • Open system: Requires injected water under hydraulic pressure, upland terrain
       • Closed system: Water supplied during permafrost aggradation, low terrain
     • Rock Glaciers
       • Tongue shaped bodies formed from frozen debris
       • Mountainous regions
     • Thermokast
       • Irregular terrain by melting ice
       • Caused through disruption in thermal equilibrium
     • Patterned ground
       • Movement of soils by frost action
     • Solifluction/gelifuction
       • Movement of water
     • Talus slope