Glaciers Prentice Hall Chapter 8, Section 4 By Rusty Sturken December, 2006 - 2009 Duluth Middle School Sixth Grade Earth Science

Glaciers A glacier is any large mass of ice that moves slowly over land. *Glaciers only form in areas where more snow falls than melts *Snow builds up year after year *Pressure on the snow at the bottom turns it into ice *Gravity pulls the glacier downhill

Glaciers A valley glacier is a long, narrow glacier that forms high in a mountain valley * flows a few centimeters to a few meters per day A continental glacier is a glacier that covers much of a continent or large island *much larger than valley glaciers *spreads out like pancake batter * cover Antarctica and Greenland

Glaciers Valley glacier Continental glacier www.uwsp.edu/.../glacier_Ellesmere_GSC.jpg pubs.usgs.gov/of/2004/1216/images/mendenhall.gif

Continental Glaciers Continental glaciers cover about 10% of Earth’s surface The glacier covering Antarctica is over 14 million square kilometers and 2 kilometers thick An Ice Age is a time when continental glaciers cover large parts of Earth’s surface * The last ice age ended 10,000 years ago. * Ice has covered 1/3 of Earth

Glacial Erosion The two processes by which glaciers erode the land are plucking and abrasion Plucking is the process when glaciers pick up rocks as they flow over the land, the rock freezes to the bottom of the glacier Abrasion is the grinding away of rock by other rock particles carried in water, ice, or wind. Rocks frozen to the bottom of a glacier scrape across rocks on the Earth’s surface.

Glacial Deposition When a glacier melts, it deposits the sediment it eroded from the land, creating various landforms. Till is the mixture of sediments that a glacier deposits directly on the surface of the Earth. A moraine is a ridge of till deposited at the edge of a glacier. A terminal moraine is the ridge of till at the farthest point reached by a glacier.

www.uwsp.edu/.../images/titles/moraines.gif Great website

Moraines Terminal moraines and end moraines are the same thing www.uwsp.edu/.../images/titles/moraines.gif http://www.belmont.sd62.bc.ca/teacher/geology12/photos/glaciers/lateral_moraine2.jpg

Long Island, N.Y. is a terminal moraine from the last ice age http://www.coolantarctica.com/Shop/cities/Long_island_small.jpg http://image.weather.com/imageat/regions/northeast_sat_720x486.jpg

Glaciers http://www.wildnatureimages.com/S%20to%20Z/SALMON-GLACIER-CAMPER..jpg http://pubs.usgs.gov/of/2004/1216/glaciertypes/images/glacierpolar1.gif http://upload.wikimedia.org/wikipedia/commons/thumb/a/a6/Tschierva_glacier_1.jpg/600px-Tschierva_glacier_1.jpg

Formations from glaciers Moraines Cirques(bowls) Arêtes Horns Fiords U-shaped valleys Glacial lakes Kettle lakes Background photo from: www.swisseduc.ch/.../icons/cirque-glacier.jpg Teton Glacier in Grand Teton National Park, Wyoming

See Page 272 Prentice Hall Science Explorer, Earth Science 2002, 2001 Pearson Education, Inc.

See Page 273 Prentice Hall Science Explorer, Earth Science 2002, 2001 Pearson Education, Inc.

Cirque A bowl-shaped hollow eroded by a glacier www.geocities.com/gibell.geo/cirque/overview.html Logan Mountains, Northwest Territories, Canada

Arête A sharp ridge separating two cirques (bowl-shaped hollows) z.about.com/d/geology/1/0/K/K/arete.jpg

Horn Sharpened peak formed when glaciers carve away the sides of a mountain. http://www.homepage.montana.edu/~geol445/hyperglac/eroland1/horn2.JPG Glacier N.P.

Fiord Form when sea level rises, filling a glacier-cut valley http://www.southlandnz.com/sections/move/fiord/

Kettle Forms when depression in till fills with water www.sfu.ca/~jkoch/older_stuff/glacier%20glossary%20photos/fiord.JPG

Fiord/ U-shaped valley http://www.arcticnet.org/00037245-007EA71E.4/pang%20fiord.jpg

Glacial Lakes Form in long basins created by plucking and abrasion Great Lakes Finger Lakes in New York www.ssec.wisc.edu/~gumley/modis_gallery/image. http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/FingerLakes_ISS010E09366_lrg.jpg Also excellent website Excellent website

Pictures for backgrounds Better font Animation THANK YOU to all of my 2006-2007 Sixth Grade students who helped me improve my Powerpoints You helped me with: Pictures for backgrounds Better font Animation Figuring out what works or doesn’t I still have a long way to go