Degradation Processes: Weathering and Soil

1. Degradation Processes: Weathering and Soil

2. Just to review a few things… Weathering: Process by which rock begins to come apart. Erosion: The weathering and transportation of material.1. Physical Weathering: Breaking up of material into smaller pieces (mechanical). 2. Chemical Weathering: A change in composition through a chemical reaction with water or weak acid.

3. Types of Soil Latosols: Tropical red earth; high precipitation and heat; reddish colour; agriculture poor due to leaching; found near equatorial. Podzols: cool, wet temperatures; ash coloured top soil; associated with coniferous forests; constant leaching; needles cause acidity and cool temperatures decrease decomposition; found in west coast of BC. Luvisols: Cool, dry temperatures; long winters with short growing seasons; gray top soil with clay in B horizon; found in Interior of BC; associated with smaller trees; need organic material to assist agriculture.

4. Types of Soils (Continued) Brunisols: occur in regions between podzols and luvisols; not as much clay as luvisols or as much iron/ aluminum as podzol; found in Kootenays and along Yukon border. Chernozemic: Black/ dark brown soil; little rain so little leaching; best soil for agriculture; cold winter and hot summer; found in Prairies; wheat. Sierozems: gray, desert, rocky and sandy; hot temperature, little rain; sparse vegetation (xerophytes); found in desert regions. Tundra: cold, dry (rain usually falls as snow); mosses and lichens dominate vegetation; poor agriculture; soil usually permafrost. Alluvial: soils created by deposition along rivers; good for agriculture since there are a lot of nutrients in them.

5. Types of Soil Degradation Desertification: lack of water Salinization: too much water Soil Movement: Creeping- expansion and contraction of soil Falling- material on steep slope falls (talus cones) Sliding- downward movement of a uniform material Flowing- downward movement of material that behaves like a fluid.

6. The Water Cycle

7. The Water Table

8. Water Table Terms Zone of Aeration: The area above the water table that contains air and water. Zone of Saturation: Area below water table that is saturated due to water being pulled down. Water Table: Ground Water; It rises and falls throughout the year.. Aquifer: Rock layer that can store a lot of water Porosity:Amount of spaces in soil. Permeability: How fast water can pass through rock layers.

9. Ground Water: The water held in pore spaces in the soil and unconsolidated materials below the surface. Due to the decay of plant material, the groundwater tends to be fairly acidic. As a result, ground water is effective at weathering limestone and creating Karst topography. As groundwater moves through limestone, it slowly dissolves the rock (creating pits and hollows on the surface). Streams can disappear underground and this contributes to the creation of caves.

10. Ground Water Creates Karst landscapes Stalagmites: Limestone that grows as a mound in a cave. Stalactites: Limestone that grows down from a cave roof (like an icicle) Pillars: When the two join together. Sinkhole: When a cave grows and the overlying land collapses. Polje:these are formed from the collapse of underground caverns or rivers. Stalagmites

11. Stalactites Pillars

12. Sinkhole

13. Polje