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Weathering, Erosion and Soil

Weathering, Erosion and Soil. Weathering. Temperature Freezing temperature causes the expansion of the molecules of substances - water expands as it freezes

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Weathering, Erosion and Soil

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  1. Weathering, Erosion and Soil

  2. Weathering

  3. Temperature Freezing temperature causes the expansion of the molecules of substances - water expands as it freezes Cracks in concrete, wood, etc. fills with water. Water freezes and expands, causing splitting and breaking apart - frost wedging, ex. pot holes. Pressure - factor of mechanical weathering. Bedrock at great depth are under pressure as over lying rock is stripped away. The bedrock at depth is exposed. Then the bedrock can expand and cracks will occur. Exfoliation - stripping of layers of rock - create a dome formation, ex. Stone mountain in Georgia Mechanical Weathering

  4. Stripping of layers of rock Creates a dome formation Ex, Stone Mountain in Georgia Half Dome Yosemite Valley California Exfoliation

  5. Rocks change composition as the result of chemical reactions. Agents - H2O, O2, CO2, and acids. Temperature tends to speed up and slow down chemical reactions *Rate of chemical Rx (reactions) doubles with each 10°C increase Chemical Weathering

  6. Chemical Weathering

  7. Universal solvent, hydrolysis - reaction of H2O and other substances Oxygen - oxidation Substance + O2 new substance Fe (Iron) + O2 (Oxygen) Fe2O3 (Rust) Al (Aluminum) + O2 Al2O3 (Aluminum Oxide) 21% of oxygen is in atmosphere Minerals - result of oxidation, Ex. Pyrite, magnetite CO2 - produced through respiration CO2 + H2O H2CO3 (Carbonic Acid, weak acid form in the atmosphere Carbonic acid reacts with calcite forms (limestone caverns) wATER

  8. Acid Precipitation Acid Precipitation - Oxidation of sulfur dioxide and nitrogen oxide - that is released by human activities SO2 Industrial emissions NO2 Motor Vehicles SO2 + O2 + H2O Sulfuric acid NO2 + O2 + H2O Nitric acid Acid Rain - PH = less than 5.6 Normal Rain - PH = 5.6 Water in lake - 6 to 8 PH Lower PH kill fish To reverse acidification Acid Ca(OH)2to the area - Calcium Hydroxide

  9. Effects of acid rain on plants

  10. 2000 years to weathering/centimeter of limestone Climate - major influence on chemical weathering variables: precipitation temperature evaporation Interactions of temperature and precipitation has the greatest effect. Chemical weathering predominates in climate with warm temperature, abundant rainfall and lush vegetation. H2O + CO2H2CO3(Carbonic acid - accelerates chemical weathering Location: Central America, S.E. Asia What effects the rate of Weathering?

  11. Physical Weathering- dominates cool, dry climates where H2O undergoes repeated freezing and thawing. Extremely cold climates has no chemical weathering Rock Type and Composition- Characteristics of rocks - hardness and resistance to breakdown is dependent on the type and composition of the rock. Easy - Sedimentary - easy to break Igneous Metamorphic - hardest Mechanical Weathering- breaking rocks in small pieces - increases surface area Topography - flat level area - rocks remain in place and undergo changes Hilly area - rocks suffer greater erosion through mass movement Weathering

  12. Erosion - movement of material Deposition - materials that are dropped in an area after movement Gravity - associated with erosion - pull materials downward “Agent of Mass Movement” (landslides, mudflows, avalanches) Running water - greatest erosional agent, stronger than wind, carries more material a greater distance Movement

  13. Gully Erosion in a Pasture Running water that becomes deep and wide (3 Meters)

  14. Rill Erosion- running water in small channels on slopes

  15. Mississippi carries 750 million metric tones of material— deposited into the Gulf of Mexico - forms the delta. Volume of river flow and the action of tides determine the shape of delta. Ocean currents and tides carve out cliffs, arches and other features. Sand particles accumulate on shorelines and form dunes and beaches Sand bars - accumulation of sand underwater create a barrier island - location: lakes, Gulf of Atlantic Coast Coastal deposition and erosion

  16. Landform Deposition

  17. Sand Bar

  18. Amazon Delta

  19. Glaciers cover 10% of the earth. Erosion is large scale and dramatic. Landscape features - waterfalls, lakes, Ex. Great Lakes, finger lakes (New York) Glacial erosion

  20. http://video.search.yahoo.com/video/play;_ylt=A0S00MufIgRRAFcA7o77w8QF;_ylu=X3oDMTBvMGQzcTByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzMg--?p=Glaciers&vid=44a347f060ab09ddfddd2ffdad4d5c0a&l=&turl=http%3A%2F%2Fts1.mm.bing.net%2Fth%3Fid%3DV.4988343346200648%26pid%3D15.1&rurl=http%3A%2F%2Fwww.5min.com%2FVideo%2FLearn-About-Glaciers-304218898&tit=Learn+About+Glaciers&c=1&sigr=11ouvmua1&fr=yfp-t-701&tt=bhttp://video.search.yahoo.com/video/play;_ylt=A0S00MufIgRRAFcA7o77w8QF;_ylu=X3oDMTBvMGQzcTByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzMg--?p=Glaciers&vid=44a347f060ab09ddfddd2ffdad4d5c0a&l=&turl=http%3A%2F%2Fts1.mm.bing.net%2Fth%3Fid%3DV.4988343346200648%26pid%3D15.1&rurl=http%3A%2F%2Fwww.5min.com%2FVideo%2FLearn-About-Glaciers-304218898&tit=Learn+About+Glaciers&c=1&sigr=11ouvmua1&fr=yfp-t-701&tt=b Learn about Glaciers

  21. http://video.search.yahoo.com/video/play;_ylt=A0S00MtABAhRWSIAbQn7w8QF;_ylu=X3oDMTBvMGQzcTByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzMg--?p=glaciers+form+montana&vid=cfe70ffb5200cdcf7a3802ef57cfef0d&l=&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DV.4614243116187834%26pid%3D15.1&rurl=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DBMslDdswGB0&tit=Canadian+Rockies+and+Glacier+National+Park+2012&c=9&sigr=11ajreimc&fr=yfp-t-701&tt=bhttp://video.search.yahoo.com/video/play;_ylt=A0S00MtABAhRWSIAbQn7w8QF;_ylu=X3oDMTBvMGQzcTByBHNlYwNzcgRzbGsDdmlkBHZ0aWQDVjEzMg--?p=glaciers+form+montana&vid=cfe70ffb5200cdcf7a3802ef57cfef0d&l=&turl=http%3A%2F%2Fts3.mm.bing.net%2Fth%3Fid%3DV.4614243116187834%26pid%3D15.1&rurl=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DBMslDdswGB0&tit=Canadian+Rockies+and+Glacier+National+Park+2012&c=9&sigr=11ajreimc&fr=yfp-t-701&tt=b Glacier National Park

  22. Finger lakes New York

  23. Areas of limited precipitation and high temperature, Ex. Death Valley Wind Erosion

  24. Wind Erosion

  25. After the Winds Subside

  26. Stops erosion, conserve moisture, trap blowing snow and protect crops - wind barriers ( wind breakers - thick line of trees) Planting methods Plowing methods Farming Methods

  27. Combine different Crops

  28. Planting Crops Perpendicular on a hill

  29. No Till Farming

  30. Strip Farming

  31. Dust Bowl Prevention

  32. Development of Soil - Soil looses covering of broken rock particles and decaying organic matter called humus. Overlays the bedrock. Result of chemical and mechanical weathering and also biological activity. Formation of Soil

  33. Soil composition - Soil forms layers. Pieces of rock are broken off from the parent rock. Soil is located above it’s parent rock. H2O sinks down carrying minerals and nutrients through the layer of the soil. Parent rock determines the kinds of minerals, proportion of mineral in soil. Length of formation time depends on the type of rock and climate conditions Soil profile- vertical segments of soil layers - well developed soil - distinct layer 3 main horizons: A - organic/humus - gradual to black color B - poorer developed - rich in clay minerals, forms hardpan layers of soil. Red or brown (iron oxide) C - Directly above bed rock, most weathered parent material soil

  34. Soil Horizons

  35. Affects the thickness of developing soil. Sloped areas cause particles, little particles are washed away. Soil then, is infertile. South facing slope has more direct sunlight / more vegetation, thick soil. *Valley - soil thick and rich. Vegetation contributes to the buildup of humus and supplies acids to promote the weathering process.  Soil Types - Appearance, rate of formation and productivity is determined by climate Topography

  36. Soil varies because of different parent rocks and undergo different climate conditions. Types of plants: animals that live there: topography: length of time the soil has been forming. Soils are classified based on climate conditions. soil

  37. 1 polar 2 temperate 3 desert 4 tropical Four types of soil

  38. Polar Soil

  39. Supports diverse environments, annual rainfall 50-60 cm, grasslands - abundance of humus, forest - aluminum rich clays Western U.S. rainfall less than 50-60 cm, support grasses and bushes Temperate Soil

  40. Temperate soil Santa Clara CA

  41. Low level precipitation - Less than 25 cm of rainfall per year - High level of salts - supports limited vegetation - light in color— composed of salts and gypsum Desert Soil

  42. Desert Soil

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