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Glacier Notes

Glacier Notes. Cryosphere. All of the frozen areas on Earth's surface where water exists in its solid form . sea ice ice shelves icebergs ice sheets glaciers. lake ice river ice snow permafrost. Glacial Overview. What are they? How do the form? How do they move?

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Glacier Notes

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  1. Glacier Notes

  2. Cryosphere All of the frozen areas on Earth's surface where water exists in its solid form • sea ice • ice shelves • icebergs • ice sheets • glaciers • lake ice • river ice • snow • permafrost

  3. Glacial Overview • What are they? • How do the form? • How do they move? • What kinds of features do they form?

  4. Glaciers Mass of ice formed by the recrystallization of snow under its own weight Compacted snow becomes “firn” More snow has to be added than melted in the previous year's worth of snowfall so that it can accumulate in layers

  5. Types of Glaciers 1. Ice sheets (continental glaciers) -- cover large areas of land 2. Valley (alpine) glaciers -- form at mountain tops and flow down valleys

  6. Glacier: a Flowing River of Ice • Mountain (Alpine) • Continental (Ice Sheets)

  7. How Glaciers Move

  8. Glacial Zones Zone of Accumulation • Snowfall exceeds ablation • Ablation – reduction in glacial ice by sublimation, melting, or calving Zone of Melting (Ablation) (Wastage) • Ablation exceeds snowfall

  9. Anatomy of a Glacier

  10. Erosional Features

  11. U-Shaped Valley / Fjord / Trough

  12. Hanging Glacier

  13. Cirque A semicircular or amphitheater-shaped feature created as glaciers scour back into the mountain

  14. Arete • Steep-sided, sharp-edged bedrock ridge formed by 2 glaciers eroding away on opposite sides of the ridge

  15. Horn A pyramid-shaped mountain peak created by several glaciers eroding away at different sides of the same mountain

  16. Glacial Striations Lines etched in bedrock under glaciers as individual particles of rock embedded in the glacier scratch the bedrock

  17. Horn Arete Cirque

  18. The Matterhorn In the Swiss alps

  19. ? ? ?

  20. Glacial Deposits • Glacial deposit is called till. • Glaciers pick up everything in their path, even the largest boulders. • Large amounts of sediment can be carried long distances by glaciers.

  21. Depositional Features

  22. Moraines • A mound or ridge of till deposited by a glacier • The different places along a glacier’s advance will result in the different types of moraines • Lateral (Sides) • Medial (Middle) • Terminal (End)

  23. Lateral Moraine Unconsolidated material deposited along the sidesof an alpine glacier

  24. Medial Moraine When two alpine glaciers flow together, their lateral moraines join, forming a medial (middle) moraine

  25. Terminal/End Moraine

  26. Formation of end moraine • The terminus of a glacier may remain stationary for years. • The sediment piles up in a ridge called an end moraine. • If this marks the furthest extent of the glacier it is a terminal moraine.

  27. Retreating Glacier End moraine

  28. medial moraine lateral moraine

  29. Esker Long ridge formed by sediment deposition in sub-glacial streams

  30. Kettle Lakes Formed by melting ice chunks in glacial debris

  31. A long, narrow, smooth hill of unstratifited glacial till. Points in the direction of flow. Drumlin

  32. Erratics Large boulders left behind after glaciers retreat

  33. Continental Glaciation Landform Features Southernmost extent of continental glacier

  34. Retreat of South Cascade Glacier, Washington

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