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GLACIERS. CHAPTER 11 GEOLOGY. Top 10 glacier facts. 10. Approximately 10 percent of the Earth is covered by glaciers; during the last Ice Age, they covered one-third of the Earth’s surface.
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GLACIERS CHAPTER 11 GEOLOGY
Top 10 glacier facts 10. Approximately 10 percent of the Earth is covered by glaciers; during the last Ice Age, they covered one-third of the Earth’s surface. 9. Glacier ice is the largest reservoir of fresh water on the planet, storing an estimated 75 percent of the world’s supply. 8. Glaciers are found in 47 countries. 7. A glacier can range in length from the equivalent of a football field to more than 100 miles. 6. The Antarctic ice sheet is actually a glacier and has existed for at least 40 million years. If it were to melt in its entirety, sea levels would rise 210 feet worldwide, according to the U.S. Geological Service.
5. Though it sits on the equator, Mount Kilimanjaro is glaciated. 4. On steep slopes, a glacier can be as thin as 50 feet. 3. Mountain valleys are typically “V” shaped before being taken oven by a glacier; during glaciation, the valley widens and deepens and thus becomes “U” shaped. 2. A single glacier ice crystal can grow to be as large as a baseball. 1. Alaska is estimated to have more than 100,000 glaciers. Most remain unnamed
What is a glacier? a thick mass of moving ice http://www.jadecoast.ca/Sawyer%20glacier.JPG
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
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
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.
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
Cirque • A bowl-shaped depression located where a glacier begins to form
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
The most famous horn in the Alps…The Matterhorn • Located on the boundary between Switzerland and Italy, the Matterhorn’s summit is 1500 feet above sea level.
Arete – spines or ridges of rock that separate glacial valleys
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
VALLEY GLACIER http://perth.uwlax.edu/faculty/stoelting/Intro/Guides/Images3/alpine_glacier_processes_side_view_800.jpg
Glaciers pick up lots of sediment as they advance over the land. http://www.geographyjim.org/Newzealandglacier.jpg
TYPES OF GLACIAL DRIFT(Sediments) • TILL- unsorted; deposited by ice • STRATIFIED DRIFT- layered; deposited by meltwater streams • OUTWASH- sorted sand; deposited by meltwater
till outwash
Erratics • Boulders carried great distance by the glacier • Don’t match surrounding rock • “strange rock”
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.
MORAINES • Deposited along edge of glacier during melting • Ridges of till • Terminal- very end of glacier • Lateral- side of glacier • Recessional- progresses behind terminal
MORAINES • MADE OF TILL http://www.helsinki.fi/~jhyvonen/PB/M/Cerro%20Tronador%20moraine-pp.JPG
terminal moraine – unsorted sediments deposited at the edge of the melting glacier
Ground Moraine- flat till deposits between recessional moraines
Moraine Deposits = unsorted sediments Moraines are made of unsorted sediments. Only mass movements and glaciers deposit unsorted sediments. Since there are no large hills or mountains in Michigan for this sediment to fall down, it must have been deposited by the glaciers.
Drumlins • Hills of sediment deposited by the glacier- till
KAMES Cone shaped deposits Deposited at end of meltwater streams Stratified drift
Meandering ridges of stratified drift Deposited by meltwater streams Mined for gravel ESKERS
Mt. Brighton Mason esker
Kettle Lakes • Made from ice blocks • Deep inland lakes • rocky