Weathering, Soil, and Erosion 12 CHAPTER Weathering, Soil, and Erosion EXIT CHAPTER 12.1 Weathering 12.2 Soil 12.3 Mass Movements and Erosion 12.4 Soil as a Resource CHAPTER OUTLINE

12 12.1 Weathering Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.1 Weathering VOCABULARY Weathering is the breakup of rock due to exposure to processes that occur at Earth’s surface. weathering mechanical weathering chemical weathering Mechanical weathering breaks down rocks without changing their composition. It includes wetting and drying, abrasion, plants and animals, upward expansion, and frost wedging. frost wedging abrasion exfoliation hydrolysis 1. Rainwater enters existing cracks in a rock. 2. The water expands as it freezes, wedging the rock apart. acid rain oxidation SECTION OUTLINE

12 12.1 Weathering Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.1 Weathering VOCABULARY Chemical weathering involves water or water vapor and changes the composition of rocks, and includes oxidation, acid precipitation, and hydrolysis. weathering mechanical weathering chemical weathering frost wedging abrasion exfoliation hydrolysis acid rain oxidation Some factors that affect the weathering rate of rocks are surface exposure, composition, and climate. SECTION OUTLINE

12 Weathering, Soil, and Erosion weathering CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering weathering chemical weathering The breakup of rock due to exposure to processes that occur at or near Earth’s surface. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

mechanical weathering 12 CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering mechanical weathering chemical weathering The breakdown of rock that takes place when a rock is broken into smaller pieces of the same material without changing its composition. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion chemical weathering CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering chemical weathering chemical weathering The breakdown or decomposition of rock that takes place when minerals are changed into different substances. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion frost wedging CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering frost wedging chemical weathering A mechanical weathering process in which water freezes in the cracks of a rock and wedges it apart. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion abrasion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering abrasion chemical weathering The wearing away of rock material by grinding action. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion exfoliation CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering exfoliation chemical weathering The peeling of surface layers from exposed bedrock. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion hydrolysis CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering hydrolysis chemical weathering The chemical reaction of water with other substances. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion acid rain CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering acid rain chemical weathering Rainwater that contains unusually high amounts of acids that can be traced back to pollutants, including sulfur dioxide, nitrogen compounds, and carbon dioxide. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 Weathering, Soil, and Erosion oxidation CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY weathering mechanical weathering oxidation chemical weathering The chemical reaction of oxygen with other substances. frost wedging abrasion exfoliation hydrolysis acid rain oxidation SECTION OUTLINE

12 12.2 Soil Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.2 Soil VOCABULARY Soil is loose, weathered rock and organic material capable of supporting rooted plants. A soil may be residual or transported, depending on its parent material. soil parent material residual soil transported soil As soils form, they develop horizons. soil profile A - horizon B - horizon C - horizon soil horizon Each horizon is composed of different amounts of organic material, minerals, and parent material. topsoil subsoil SECTION OUTLINE

12 12.2 Soil Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.2 Soil VOCABULARY A soil’s composition depends on many factors, one of the most important of which is climate. soil parent material residual soil transported soil ICE ARCTIC SOILS TEMPERATE GRASSLAND SOILS TEMPERATE FOREST SOILS TROPICAL GRASSLAND SOILS DESERT SOILS TROPICAL FOREST SOILS soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion soil CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material soil residual soil Loose, weathered rock and organic material in which plants with roots can grow. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion parent material CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material parent material residual soil The rock material from which a soil is formed. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion residual soil CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material residual soil residual soil Soil whose parent material is the local bedrock beneath it. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion transported soil CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material transported soil residual soil Soil that formed from parent material left by winds, rivers, or glaciers or soil that itself was moved from its original location. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion soil profile CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material soil profile residual soil A cross section of soil layers that displays all soil horizons. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion soil horizon CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material soil horizon residual soil A soil layer with physical and chemical properties that differ from those of adjacent soil layers. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion topsoil CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material topsoil residual soil The A-horizon of soil; contains organic material, or humus, that forms from decayed plant and animal materials. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12 Weathering, Soil, and Erosion subsoil CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil parent material subsoil residual soil The B-horizon of soil; contains clay and iron oxides washed from the topsoil. transported soil soil profile soil horizon topsoil subsoil SECTION OUTLINE

12.3 Mass Movements and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.3 Mass Movements and Erosion VOCABULARY Mass movements involve the downward transport of rock materials by gravity. mass movement erosion talus landslide creep slump earthflow mudflow volcanic neck Mass movements include creep, slump, earthflows, and mudflows. SECTION OUTLINE

12.3 Mass Movements and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.3 Mass Movements and Erosion VOCABULARY Erosion is the removal or transport of rock materials by natural agents such as water and wind. mass movement erosion talus The rate of erosion is influenced by the climate of a region and the composition of rock. landslide creep slump The outer layers of a volcano eroded away leaving behind a more resistant volcanic neck. earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion mass movement CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion mass movement talus The downslope transportation of large masses of earth materials by gravity. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion erosion talus The removal and transport of materials by natural agents such as wind and running water. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion talus CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion talus talus Cliff rock fragments that have been weathered loose and pulled down by gravity. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion landslide CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion landslide talus The rapid movement of a mass of bedrock or loose soil and rock down the slope of a hill, mountain, or cliff. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion creep CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion creep talus The slow, often imperceptible, movement of soil down a slope. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion slump CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion slump talus A mass movement in which a block of land tilts and moves downhill along a surface that curves into the slope. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion earthflow CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion earthflow talus The downslope movement of a mass of earth materials that have been saturated with water. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion mudflow CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion mudflow talus The downslope movement of water that contains large amounts of suspended clay and silt. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 Weathering, Soil, and Erosion volcanic neck CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY mass movement erosion volcanic neck talus The solidified lava filling the central vent of an extinct volcano. landslide creep slump earthflow mudflow volcanic neck SECTION OUTLINE

12 12.4 Soil as a Resource Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME 12.4 Soil as a Resource VOCABULARY Soil depletion and salinization are problems that affect soil fertility. Appropriate farming practices can help protect soil fertility. soil fertility soil depletion salinization Contour plowing, strip cropping, no-till farming, windbreaks, and terracing are methods used to prevent soil erosion. Terraces Windbreaks SECTION OUTLINE

12 Weathering, Soil, and Erosion soil fertility CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil fertility soil depletion soil fertility salinization The ability of soil to grow plants. SECTION OUTLINE

12 Weathering, Soil, and Erosion soil depletion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil fertility soil depletion soil depletion salinization The process by which soil gradually becomes so lacking or depleted in nutrients that it can no longer grow a crop. SECTION OUTLINE

12 Weathering, Soil, and Erosion salinization CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY soil fertility soil depletion salinization salinization A soil condition caused by the evaporation of irrigation water, which leaves too much mineral matter on the soil’s surface for crops to grow. SECTION OUTLINE

12 Weathering, Soil, and Erosion I. Weathering CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY I. Weathering weathering A. Mechanical Weathering mechanical weathering 1. Ice and Water chemical weathering 2. Abrasion frost wedging 3. Plants and Animals abrasion 4. Upward Expansion exfoliation B. Chemical Weathering hydrolysis 1. Water and Chemical Weathering acid rain 2. Oxygen and Chemical Weathering oxidation C. Rates of Weathering 1. Surface Exposure 2. Composition of Rock 3. Climate KEY IDEA SUMMARY

12 Weathering, Soil, and Erosion II. Soil A. How Soil Forms CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY II. Soil soil A. How Soil Forms parent material B. Soil Composition residual soil transported soil soil profile soil horizon topsoil subsoil KEY IDEA SUMMARY

III. Mass Movements and Erosion 12 CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY III. Mass Movements and Erosion mass movement A. Mass Movements erosion 1. Creep talus 2. Slump landslide 3. Earthflows creep 4. Mudflows slump B. Erosion and Landforms earthflow mudflow volcanic neck KEY IDEA SUMMARY

12 Weathering, Soil, and Erosion IV. Soil and Resource CHAPTER Weathering, Soil, and Erosion CHAPTER HOME VOCABULARY IV. Soil and Resource soil fertility A. Soil Fertility soil depletion 1. Soil Depletion salinization 2. Salinization B. Erosion and Soil Conservation KEY IDEA SUMMARY

12 Weathering, Soil, and Erosion CHAPTER Weathering, Soil, and Erosion CHAPTER HOME This is the end of the chapter presentation of lecture notes. Click the CHAPTER HOME button or exit the presentation.