1 / 14

Weathering, Erosion, & Soil

Weathering, Erosion, & Soil. Ch. 7: Part 1. Weathering. Weathering : Process by which rocks on or near Earth’s surface break down and change Types of Weathering :

kim-hinton
Download Presentation

Weathering, Erosion, & Soil

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Weathering, Erosion, & Soil Ch. 7: Part 1

  2. Weathering • Weathering: Process by which rocks on or near Earth’s surface break down and change • Types of Weathering: • Mechanical: process by which rocks and minerals break down into smaller pieces (does not change rocks composition, only size and shape. • Chemical: process by which rocks and minerals undergo changes in their composition as a result of chemical reactions

  3. Factors of Mechanical Weathering • Temperature: Drop in temperature causes water to begin to freeze, water then expands, taking up more space than in liquid form • - Frost Wedging: repeated thawing and freezing of water in the cracks of rocks causing them to break apart (example: Potholes)

  4. Factors of Mechanical Weathering • 2. Pressure: Layers of rocks put pressure on rocks below; when rock layers are removed (exfoliation), pressure is reduced, causing expansion of the rock and long, curved cracks to form • Exfoliation: outer rock layers are stripped away

  5. Factors of Chemical Weathering • Water: can dissolve many kinds of minerals and rocks; Can react with other substances (hydrolysis) which occurs during the decomposition of one mineral to another. • 2. Oxygen: can chemically react with other substances (oxidation); ex: oxygen in the atmosphere can combine with iron in rocks and minerals

  6. Factors of Chemical Weathering • 3. Carbon Dioxide: atmospheric gas when combined with water in the atmosphere produces weak carbonic acid; can react with certain minerals to dissolve rocks • 4. Acid Precipitation: caused by the oxidation of sulfur dioxide and nitrogen oxides in the atmosphere by human activity; has a pH below 5.6; creates problems for many organisms living in aquatic environments

  7. What affects the rate of weathering? • Climate: interaction between temperature and precipitation • -Chemical weathering: common in warm temps, abundant rainfall, lush vegetation • -Mechanical weathering: cool, dry climates where water undergoes repeated freezing and thawing • Rock Type and Composition: sedimentary rocks are more easily weathered than harder igneous and metamorphic • Surface area: more surface area=more weathering • Topography: slope of the landscape determines the weathering

  8. Erosion and Deposition

  9. Erosion • Erosion: removal of weathered rock and soil from its original location • Deposition: After the material is transported they are dropped into another location

  10. Gravity’s Role in Erosion • Force of gravity tends to pull all materials downslope. • Without gravity, glaciers would not move downslope and streams would not flow • Also an agent in mass movements: landslides, mudflows, and avalanches.

  11. Erosion by Running Water • **Swiftly flowing water has greater erosional power than wind and can also carry more material along with it and over a greater distance. • Rill Erosion: erosion by running water in small channels, on the side of a slope; form on a slope • Gully Erosion: when channel becomes deep and wide; can be more than 3 m deep and causes major problems in farming and grazing areas • **Weathering and Erosion occur also in oceans and islands: currents, waves, and tides carves out cliffs, arches, and more and a lot of the weathering and erosion occurs along the shorelines.

  12. Glacial Erosion • -Glaciers scrape and gouge out large sections of Earth’s landscape; they are so dense and have ability to carry huge rocks and other debris long distances • -Leave behind valleys with waterfalls, lakes, and variously shaped deposits of sediment

  13. Wind Erosion • Major erosional agent in areas with limited precipitation and high temperatures • Can easily pick up and move the fine, dry particles • Effects can be dramatic and devastating • Can damage natural features and human made structures • Very common in Death Valley • Shore areas also experience wind erosion • Running water and glacial activity still more powerful • Wind barriers can reduce the effects of wind erosion for farmers (trees and other plants)

  14. Erosion by Plants, Animals, and Humans • -Plants and animals move Earth’s surface materials from one place to another • -Animals burrow, humans excavate areas and move soil, planting a garden, developing new athletic fields, building a highway all result in the moving of earth’s materials from one place to another • -Effects of erosion by plants, animals, or humans is minimal compared to water, wind, or glaciers.

More Related