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Formation and Features of Glaciers

Learn about how glaciers form and the various landforms they create, including moraines, kettle lakes, drumlins, and eskers.

carolwest
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Formation and Features of Glaciers

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  1. GLACIERS CHAPTER 5 HONORS EARTH SCIENCE

  2. What is a glacier? a thick mass of moving ice http://www.jadecoast.ca/Sawyer%20glacier.JPG

  3. How do glaciers form? Step 1: Snow accumulates. More snow falls during the winter than melts in the summer.

  4. Trans Labrador Highway

  5. Step 2: Snow changes to firn. As snow accumulates, its weight compress the individual snowflakes to form firn. FIRN http://www.gsw.edu/~bcarter/physgeol/glac/firn.jpg

  6. Firn http://crevassezone.org/Photos/Graphics/3441L-(Firn).jpg

  7. Step 3: Firn is compressed to form solid glacial ice. http://patti.tensegrity.net/album/alaska/thompson/ice4.jpg

  8. http://www.asf.alaska.edu:2222/img/firn_diagram.gifhttp://207.239.98.44/IcelandI%20232.jpghttp://www.asf.alaska.edu:2222/img/firn_diagram.gifhttp://207.239.98.44/IcelandI%20232.jpg

  9. Step 4: The ice begins to move. Plastic flow- weight of glacier moves out like pancake batter http://www-math.science.unitn.it/Bike/Countries/Europe/Tour_Reports/Tour_of_the_Alps/Gallery/glacier.jpg

  10. When the climate cooled… Ice advanced over the land, moving southward from Canada over the Great Lakes Region.

  11. Glaciar Perito Moreno, in Santa Cruz province, Argentina. It hasn’t happened since 1988 and it is said to be one of the most extraordinary natural events in the world. - Roberto Cerrudo

  12. Glacier terms • Zone of Ablation- melting • Zone of Accumulation- snow accumulates • Crevasse- cracks • Advance- more accumulation than melting • Retreat- more melting than accumulation

  13. VALLEY GLACIER http://perth.uwlax.edu/faculty/stoelting/Intro/Guides/Images3/alpine_glacier_processes_side_view_800.jpg

  14. How do glaciers erode the surface? • Plucking –freeze/thaw process lifts particles into ice Striations- parallel scratches made from rocks in ice scraping against bedrock

  15. Glacial Striations Granite Island, Lake Superior MI Calumet, MI N47°14’77’’ W88°26’82’’

  16. Kelly’s IslandGlacial grooves

  17. Glaciers pick up lots of sediment as they advance over the land. http://www.geographyjim.org/Newzealandglacier.jpg

  18. TYPES OF GLACIERS • Alpine (Valley)Glaciers – glaciers that form at high elevation in mountain valleys • Ice sheets or Continental Glaciers form in polar regions such as Greenland and Antarctica.

  19. http://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_9/geo_images_9/Fig9.20.gifhttp://daac.gsfc.nasa.gov/DAAC_DOCS/geomorphology/GEO_9/geo_images_9/Fig9.20.gif

  20. Cirque • A bowl-shaped depression located where a glacier begins to form

  21. http://crevassezone.org/Photos/Graphics/4163L-(Cirque).jpg

  22. Horn Kinnerly Peak - Glacier National Park • A tall, pointed rock peak left at the top of a mountain http://www2.nature.nps.gov/geology//parks/glac/car0348.jpg

  23. The most famous horn in the Alps…The Matterhorn • Located on the boundary between Switzerland and Italy, the Matterhorn’s summit is 4478 m above sea level.

  24. Arete – spines or ridges of rock that separate glacial valleys

  25. U-shaped Valley - Yosemite National Park

  26. V-shaped valleys become U-shaped valleys as glaciers move through them… Step 2 Step 1 A typical river valley Over time, running water cuts a deeper V-shape. Step 3 Glacier fills valley, widening and straightening the channel Step 4 Glaciers melt leaving a U-shaped valley

  27. Hanging Valley • a small valley that has not eroded as deep as the main valley that it is connected to • Waterfalls often form at hanging valleys.

  28. TYPES OF GLACIAL DRIFT(Sediments) • TILL- unsorted; deposited by ice • STRATIFIED DRIFT- layered; deposited by meltwater streams • OUTWASH- sorted sand; deposited by meltwater

  29. Erratics • Boulders carried great distance by the glacier • Don’t match surrounding rock

  30. Erratics along Lake Michigan Shoreline

  31. TYPES OF GLACIERS • Alpine (Valley)Glaciers – glaciers that form at high elevation in mountain valleys • Ice sheets or Continental Glaciers form in polar regions such as Greenland and Antarctica.

  32. MORAINES • Deposited along edge of glacier during melting • Terminal- very end of glacier • Lateral- side of glacier • Recessional- progresses behind terminal

  33. MORAINES • MADE OF TILL- unsorted sediment http://www.helsinki.fi/~jhyvonen/PB/M/Cerro%20Tronador%20moraine-pp.JPG

  34. terminal moraine – unsorted sediments deposited at the edge of the melting glacier

  35. Ground Moraine- flat till deposits between recessional moraines

  36. Kettle Lakes • Made from ice blocks

  37. Kettle Lakes • Kettle lakes form when blocks of ice break off the front edge of a glacier, become buried by sediment. The ice melts leaving a hole which fills with water creating a lake.

  38. Drumlins • Hills of sediment deposited by the glacier- till

  39. Drumlin Formation

  40. Winding ridges of stratified drift Deposited by meltwater streams Mined for gravel ESKERS

  41. KAMES Cone shaped deposits Deposited at end of meltwater streams Stratified drift

  42. Outwash plain

  43. What glacial landform are the arrows pointing to?

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