HTML University

Science Dept.

Geology and Soils GEO 100 Notes
Glaciation

1. Types of Glaciers
   1. Alpine or Valley

   2. Continental Ice Sheet
      1. Calving

      2. Icebergs

   3. Ice Caps

2. Formation
   1. Snow -> Neve (Firn) -> Glacial Ice

   2. Thickness = 100' or More

   3. Accumulation vs Ablation (Evaporation, Sublimation and Melting)

   4. Zone of Accumulation

   5. Zone of Ablation or Wastage

   6. Snow Line

   7. Advancing

   8. Retreating

3. Movement
   1. Regelation

   2. Plastic Flow

   3. Rigid Zone

   4. Shear

   5. Basal Sliding

   6. Surging

   7. Crevasses

4. Rates
   1. Faster in Middle

   2. Alpine Glacier ~ 90 to 150 m/yr (in Switzerland one alpine glacier moved 180 m/yr)

   3. Outlet Glacier ~ 400 m/yr

   4. Ice Shelf ~ 1000 m/yr (in Greenland 8 km/yr)

5. Mechanism of Erosion
   1. Abrasion
      1. Glacial Polish

      2. Glacial Striations

      3. Glacial Grooves

      4. Glacial Chattermarks

   2. Quarrying

   3. Topside Transport

   4. Materials Derived
      1. Till

      2. Erratics

      3. Rock Flour and Glacial Milk

6. General Features of Glacial Erosion
   1. Continental
      1. U shaped Valleys

      2. Ramped and Plucked Topography

      3. Striae

      4. Grooves

      5. Moulin

      6. Truncated Spurs

      7. Hanging Valleys

      8. Fjords

   2. Alpine
      1. U shaped Valleys

      2. Striae

      3. Grooves

      4. Moulin

      5. Bergschrund

      6. Cirques and Tarns

      7. Aretes

      8. Horns

      9. Cols

      10. Paternoster Lakes

      11. Truncated Spurs

      12. Hanging Valleys

      13. Fjords

7. Glacial Drift
   1. Unsorted
      1. Glacial Erratics (a, c)

      2. Till (a, c)

      3. Drumlin (c)

      4. Lateral Moraine (a)

      5. Medial Moraine (a)

      6. Ground Moraine (a, c)

      7. Recessional Moraine (a, c)

      8. Terminal Moraine (a, c)

   2. Sorted
      1. Glacial Lake Clays and Varves(a, c)

      2. Deltas (a, c)

      3. Outwash (a, c)

      4. Outwash Plains, (a, c)

      5. Outwash Plains, Pitted (a, c)

      6. Kettles and Kettle Lakes (a, c)

      7. Esker (a, c)

      8. Kame Terrace (a, c)

      9. Braided Streams (a, c)

8. The Glacial Ages
   1. Teller

   2. Agassiz

9. Glacial Rebound
   1. Some Fast Rates ~ 2 cm/yr

   2. Hudson's Bay Has Risen 300 m Since Last Glaciation

   3. Glacial Lake Hitchcock in the Connecticut River Valley

10. Causes of Glaciation
    1. Oceanic Controls

    2. Amospheric Controls - CO₂

    3. Continental Drift

    4. Astronomical - Milankovitch Theory
       1. Variation in Orbit

       2. Variation in Inclination of Rotation

    5. Glacial Ice Controls

11. Selected Glacial Web Sites