July 19, 2013

1. Landforms Geography Glaciers July 19, 2013

2. Development of a Glacier Commonwealth Glacier, Antarctica

3. Glacial Formation

4. Glacial Mass Budget

5. Glacial Mass Budget

6. Glacial Movement • Glaciers move through internal deformation • Interior of glacier like malleable plastic

7. Glacial Movement

8. Glacier Types • Mountain Glaciers • Ice Cap – Continuous sheet of ice covering entire landscape • Ice Field – Buries all but tallest mountains – can be very thick • Alpine Glacier – Flows down valleys away from high country • Cirque - Bowl-shaped depression on mountain flank due to glacial erosion – snow source

10. Alaskan Glaciers Hubbard Glacier

11. Tidewater Glacier

12. Continental Glaciers • Huge ice masses covering a large part of a continent or large island – also called ice sheets • More than 3000 m deep in places • Covers most of Antarctica and Greenland • Weight of ice presses lithosphere down into asthenosphere, called isostatic depression

13. Continental Glaciers

14. Glacial Landforms – Central Park, NYC

15. Glacial Erosional Landforms

16. Alpine Erosional Landforms • Glacial Erosion: • Cirque – bowl-like feature on mountain flanks • Tarn – small lake in bottom of cirque • Arête – narrow, steep ridges between cirques • Horn – mountain with 3 or more arêtes at summit • Glacial Trough – u-shape valley eroded by glacier • Hanging Valley – side trough above main trough – possible waterfall

17. Alpine Erosional Landforms Cirque Horn “Matterhorn” Glacial Trough

18. Glacial Depositional Landforms (Till) • Glacial Till – sediment directly deposited by glacier – many particle sizes • Moraine – winding ridge formed by till at the front or side of glacier – Moraine types: • Lateral – along former edges of glacier • Terminal – along front of former glacier • Recessional – formed as glacier recedes • Medial – between 2 glaciers • Ground – irregular deposition as glacier recedes

19. Glacial Depositional Landforms (Till)

20. Glacial Depositional Landforms (outwash) • Glacial Outwash – sediments deposited by water out & under a glacier as it melts – forms Outwash Plain, flat feature in front of former glacier • Kame – large mound deposited near glacier front • Esker – winding ridge from water flowing in tunnel through ice under glacier • Kettle Lake – big ice block fallen off glacier front is buried by outwash, melts later forming lake

21. Glacial Depositional Landforms