Periglaciation

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Slides demonstrating features and processes of Periglaciation.

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Periglaciation

  1. 1. PERIGLACIATION<br />M J Rollins<br />(Muppetmaster)<br />
  2. 2. Distribution of Permafrost<br />
  3. 3. Periglaciation:- Permafrost<br />“near to or on the fringe of an ice mass”<br />Active Layer<br />Continuous<br /> Permafrost<br />Talik<br />
  4. 4. Periglaciation:- Distribution of Permafrost<br />Lower Angle of incidence = less sunlight<br />UK Lat<br />
  5. 5. Periglacial Processes and Features<br />
  6. 6. Processes and Features<br />Ice crystals and lenses<br />Sorted Stone Polygons(stone circles)<br />About 1 metre across<br />Frost heave pushes stones to the surface which roll down the sides.<br />
  7. 7. Processes and Features<br />Stones<br />Ground Surface due to heave<br />The soil and stones move upwards due to ice crystal and frost heave<br />Ground Level in Winter<br />Ground Level in Summer<br />Frost Heave<br />The soil move downwards due to melting but ice crystal beneath stones stop them returning to original position. <br />Ground Level in Summer<br />Stones roll down to the bottom of the slope forming a circle.<br />
  8. 8. Processes and Features<br />Stone Stripes<br />Stone Circles form on a gentle slope and slowly move down the slope, stretching the circles into lines. Image pulling an elastic band!!!!<br />
  9. 9. Processes and Features<br />Stone Stripes<br />Stone Circles form on a gentle slope and slowly move down the slope, stretching the circles into lines. Image pulling an elastic band!!!!<br />
  10. 10. Processes and Features<br />Ground Contraction<br />Ice Wedges and patterned ground<br />
  11. 11. Processes and Features<br />Freezing of Ground Water<br />Pingos<br />50 m high<br />500 m diameter<br />
  12. 12. Pingo not Pingue<br />
  13. 13. Processes and Features<br />Pingos<br />Frozen lake insulates ground<br />Unfrozen Talik<br />Permafrost<br />Permafrost<br />ICE CORE<br />Ice core<br />Advancing Permafrost<br />Advancing Permafrost<br />Ice core expands upwards due to increased hydrostatic pressure <br />
  14. 14. Processes and Features<br />Pingos<br />
  15. 15. Processes and Features<br />Collapsed Pingo<br />As the rupture Pingos ice core is subjected to heat it collapses, creating Collapsed Pingo<br />
  16. 16. Processes and Features<br />Water enters cracks and joints, freezes, expands (9%) repeatedly causing rock to frost shatter.<br />Weathering<br />Physical Weathering<br />Frost shattering creates a Sea of Rock called a FELSEN MEER<br />
  17. 17. Processes and Features<br />Mass Movement<br />Solifluction Lobes<br />Soil Creep<br />Soil thaws, becomes waterlogged and lobes of soil move down slope slowly.<br />

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