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Science project chapter 12. 3, 12.4


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Science project chapter 12. 3, 12.4

  1. 1. Mass Movements and Erosion Soil as a resource Debbie Suzaña Michelle German Science 9th February 22nd, 2013 Miss Chalas
  2. 2. Mass MovementsMass movements refer to the downward transportation ofweathered materials by gravity. Landslides and rock falls areexamples of very sudden movements of this type. Of coursegeological agents such as water, wind and ice all work with gravityto cause a leveling of land.
  3. 3. Types of mass movement are distinguished based on how the soil,regolith or rock moves down slope as a whole.• Soil creep: is a long term process. The combination of small movements of soil or rock in different directions over time are directed by gravity gradually down slope. The creep makes trees curve to maintain their perpendicularity even if they lose their root footing.
  4. 4. A slump: is a form of mass wasting that occurs when acoherent mass of loosely consolidated materials or rocklayers moves a short distance down a slope.
  5. 5. Earthflows • MudflowsAn earthflow is a down slopeviscous flow of fine-grained A mudflow is the most rapid andmaterials that have been fluid type of downhill mass wasting.saturated with water, and It is a rapid movement of a largemoves under the pullof gravity. They are an mass of mud formed fromintermediate type of mass loose soil and water.wasting that isbetween downhillcreep and mudflow.
  6. 6. Erosion and landforms• Erosion is the removal and transport of materials and it can be caused naturally or through artificial means.• One of the most powerful causes of erosion is water. Water is sometimes called the universal solvent, because it is so effective at dissolving and changing things.• Rain and runoff contribute to erosion, as do glaciers, snow, and ice. Ice can be particularly insidious, because it will literally rip rock and soil apart as it expands and contracts. Many seashores distribute spectacular examples of water erosion, in the form of huge terraces of rocks slowly worn away by the ocean.
  7. 7. A resource is a source or supplySoil as a Resource from which benefit is produced. Soil is an important resource that can be conserved and protected. Because soil support plant life, which in turn support animal and human life, it is an important renewable resource.
  8. 8. Areas with the most fertile soil are often the same places where people want to build houses. Thus, it is important to conserve and protect the soil that is available as a resource. Soil fertilitySoil fertility is the ability of soil to grow plants. Theproportions of mineral matter, water, and organicmatter in soil determine the types of plants that willgrow in the soil. A number of problems, which includesoil depletion and salinization, threaten soil fertility.
  9. 9. Soil depletionCrop plants and natural vegetation use up nutrients in soil.When the plants die, they decompose in the ground, andthe nutrients are returned to the soil. When the crops areharvested, however, the nutrients are removed from thesoil. Soil depletion occurs when the soil gradually becomes so lacking or depleted in nutrients that it can no longer grow a usable crop.
  10. 10. • Irrigation can make desert soils very Salinization fertile. The problem, however, is that the water brought in to irrigate a desert contains dissolved minerals. In time, the soil contains so much mineral matter from the evaporated irrigation water that the soil can no longer sustain crop growth a process called salinization.
  11. 11. Erosion and soil conservationFor farms to remain productive, soil erosion must be controlled using soil conservationmethods: Windbreaks, also known as shelterbelts, are belts of trees planted along the edges of fields. These trees slow and reduce wind erosion. CONTINUE…
  12. 12. Contour farming is a method that inhibits waterfrom flowing rapidly downhill and carrying soil with it. Is utilized in irrigation-dependent regions where slope are moderately steep.Terrace uses steps, that are built into the side of a mountain or hill. Flattening a slope into terraces slows the speed of runoff. Strip – cropping is a method of farming used when a slope is too steep or too long, when one does not have an alternative method of preventing soil erosion.
  13. 13. Erosion