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GLACIERS AKA ICE SHEETS

GLACIERS AKA ICE SHEETS. GLACIER. natural accumulation of land ice showing movement at some time great ice sheets have waxed and waned over the surface of the Earth causes for the increase and decrease in ice sheets are still uncertain, probably not one single thing

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GLACIERS AKA ICE SHEETS

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  1. GLACIERS AKA ICE SHEETS

  2. GLACIER • natural accumulation of land ice showing movement at some time • great ice sheets have waxed and waned over the surface of the Earth • causes for the increase and decrease in ice sheets are still uncertain, probably not one single thing • http://www.pbs.org/wgbh/nova/vinson/glac-nf.html

  3. CAUSES OF GLACIATION • CLIMATE CHANGE • Earth has experienced many climate changes • change in Earth temperature and air/water circulation • decrease of  4o to 5o C (especially summer) • large increase in the amount of snowfall in subarctic and arctic regions

  4. SUGGESTED THEORIES FOR CLIMATE CHANGE • reductions in solar radiation due to meteorite collisions with the Earth, • increased volcanism • shifting location of continents • uplift of vast mountain regions • Milankovitch Cycles

  5. MILANKOVITCH CYCLES • MilutinMilankovich – Serbian Astrophysicist • thought to cause the necessary change to decrease global temperatures. • Earth's orbit is elliptical, over periods of 100,000 years the shape varies • changes in orbit have been matched with ocean sediments that record the history of glacial stages • cycles of warming and cooling match with the estimated dates of glacial periods • Earth "wobbles" on its axis which alters the amount of solar radiation reaching the Earth

  6. Ice Sheet Structure • zone of accumulation, the portion of the glacier over which accumulation exceeds ablation • zone of ablation is the loss of ice (or snow) from the glacier • equilibrium line is the boundary between these two zones • If accumulation > ablation the glacier will grow • If ablation > accumulation, the glacier will retreat

  7. Ice Sheet Structure

  8. Continental • Form on continents, flat land Global distribution of continental glaciers Ellesmere Island, Canada

  9. Alpine • Form in mountains Jungfrau, Switzerland Nisqually , Mount Ranier

  10. Piedmont • Form by combining of alpine glaciers Malaspina Glacier, Alaska (landsat) Switzerland

  11. Icebergs • Pieces of glaciers that have broken off into water. • Do you know what this process is called? Glacier Bay , Alaska

  12. Ablation • sublimation - solid to gas, ice (firn) to water vapor • wind erosion – just like sand blowing away on a beach • melting – ice changing from solid to liquid form • evaporation - liquid to gas • calving – process of glaciers breaking off into bodies of water, produces icebergs

  13. Sublimation Ablation on Glacier de Tsanfleuron, Switzerland

  14. Calving

  15. What makes glaciers melt? • List at least 3 things in your notes

  16. REFERENCES • http://www.uwsp.edu/geo/faculty/ritter/geog101/textbook/glacial_systems/glaciation_causes.html • http://www.worldviewofglobalwarming.org/pages/glaciers.html • http://www.commondreams.org/headlines02/0925-05.htm • http://www.space.com/scienceastronomy/planetearth/pumpkin_planet_021205.html • http://www.uwsp.edu/geo/faculty/ritter/geog101/uwsp_lectures/lecture_glacial_processes.html • http://www.swisseduc.ch/glaciers/glossary/ablation-en.html • http://www.pbs.org/wgbh/nova/vinson/glac-nf.html • http://www.swisseduc.ch/glaciers/glossary/ablation-en.html

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