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How do Glaciers affect the land? WED V17
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What is a glacier? 0 A large, long-lasting mass of ice which forms on land and moves downslope because of gravity.
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What metaphors do we use for glaciers? 0 Glaciers are often referred to as a River of Ice or 0 Bulldozer of Ice
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How do glaciers form?
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http://library.thinkquest.org/3876/images/howgla.gif
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How do glaciers form? Glaciers form over many years in places where the snowfall in winter exceeds the snow melt in summer Gravity pulls the ice down the hill
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http://www.swisseduc.ch/glaciers/earth_icy_planet/icons-11/20.jpg
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What are the two types of glaciers? Alpine and Continental
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Alpine Glaciers 0 A.k.a. Valley Glaciers 0 form near mountain tops and slide down the valleys 0 They can be hundreds of feet thick.
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Tyndall Glacier, Alaska
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Aletsch Glacier, Switzerland 115 sq miles http://travelguide.all-about-switzerland.info/pictures-famous-swiss-glaciers.html
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Continental Glaciers
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0 cover large areas (Antarctica, Canada) 0 can be 2 – 3 miles thick
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0 Weight of the ice depresses the ground 0 When these glaciers melt the land ‘rebounds’ 0 Some areas depressed during the last ice age are still rising
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http://www.prolitegear.com/prolitegear/images/large/antarctica_02_lg.jpg
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http://exposedplanet.com/images/antarctica-group-sled-vinsonbc-camp1.jpg
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http://exposedplanet.com/images/mountain-rangefrom-ph-antarctica.jpg
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What are the Landscape Features of Glaciated Areas?
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What are the landscape features left by Alpine or mountain glaciers? 0 Till- direct deposit of glacier; unsorted sediment 0 Mountain shape: 0 Rugged landscapes 0 Jagged peaks 0 U-shaped valley 0 Moraine- a mass of till
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Rugged Landscapes Jagged Peaks
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Northeast-looking oblique aerial photograph showing the snow-covered summit accumulation area of Mount Fairweather, Fairweather Range, Glacier Bay National Park, Alaska.
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Materhorn http://www.kuleuven.ac.be/geologie/geo-algemeen.html
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West-looking photograph showing an angular arete ridge, composed of schist, on the upper Taku Glacier, Juneau Icefield, Tongass National Forest, Coast Mountains, Alaska.
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U-Shaped Valley
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http://www.nps.gov/history/history/online_books/brochures/1936/glac/ima ges/fig13c.jpg River ValleyGlacial Valley
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Moraine 0 Mass of till (unsorted sediment) left by a glacier
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http://www.yosemite.ca.us/library/geologic_story_of_yosemite/images/62.jpg
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The u-shaped valley to the right side of the photo is the ice-free valley of Talkeetna Glacier, Talkeetna Mountains, Alaska. Note cirque at the top of the valley on the left.
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Aletsch Glacier, Switzerland http://travelguide.all-about-switzerland.info/pictures-famous-swiss-glaciers.html
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Ground Moraine
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Terminal Moraine
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Mendenhall Glacier, Tongas National Park
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What are the characteristics left by Continental Glaciers? 0 Valleys- u shaped 0 Till - unsorted sediment 0 Kettle lakes 0 Scratches and grooves 0 Drumlins
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Kettle Lake http://www.scienceclarified.com/images/uesc_06_img0334.jpg
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http://dnr.metrokc.gov/wlr/waterres/smlakes/LakeStewWeb25/GeoDrawing.JPG
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Finger Lakes 0 streams and lakes were modified by glaciers 0 Retreating glaciers deposited recessional moraines that blocked the water flow and created deep lakes 0 Examples 0 Seneca lake: 40 miles long, 618 feet deep 0 Cayuga: 40 miles long, 435 feet deep
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http://upload.wikimedia.org/wikipedia/commons/5/5f/Fingerlakesmap.png
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NASA photo
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Striations (Scratches) http://images.google.com/imgres?imgurl=http://education.usgs.gov/schoolyard/IMAGES/GlacialStriations2.jpg&imgrefurl=http://educatio n.usgs.gov/schoolyard/CoolGeologyActivity.html&h=297&w=447&sz=45&hl=en&start=1&tbnid=y1qmEFaxgJ64ZM:&tbnh=84&tbnw=12 7&prev=/images%3Fq%3Dglacial%2Bstriations%26gbv%3D2%26svnum%3D10%26hl%3Den
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Grooves
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Polished Rock http://3dparks.wr.usgs.gov/nyc/images/fig21.jpg
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Drumlin http://oz.plymouth.edu/~sci_ed/Turski/Courses/Earth_Science/Images/4.drumlin.jpg
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http://geoscape.nrcan.gc.ca/calgary/geotour/6_e.php
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A SWARM OF DRUMLINS http://www.drumlinarealandtrust.org/images/drumlins.jpg
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Icebergs Form when chunks of ice ‘calve’ off the front of the glacier and land in the water
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http://images.google.com/imgres?imgurl=http://www.atacamaphoto.com/antarctica/antarctica22.jpg&imgrefurl=http://www.atacamaphoto.com/antarctica/antarctica22.htm&h=408&w=608&s z=101&hl=en&start=37&tbnid=raJxaBCeP2TyMM:&tbnh=91&tbnw=136&prev=/images%3Fq%3Dantarctica%26start%3D20%26gbv%3D2%26ndsp%3D20%26hl%3Den%26sa%3DN
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Iceberg in Antarctica
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Floating Icebergs
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A Zodiak is cruising along a glacier front, showing the tremendous size of the ice blocks
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Giant Iceberg
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Gentoo penguin family, Antarctica
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What are the tell-tale signs that a glacier was in the area? 0 ________________ valley 0 ________________ sediment 0 ________________ in bedrock
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See you in class!
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