CHAPTER 14 Weathering SECTION 2 Rates of Weathering

CHAPTER 14: Weathering

SECTION 2: Rates of Weathering

Differential Weatherin g • Softer rocks weather faster, based on chemical composition • Hard rock – ie, Quartz resistant Devil’s Tower – weathering & erosion of cone Shows joints – areas of weakness

Rock Compositio • Chemicaln composition & how they are cemented together • Limestone weathers faster than conglomerates & sandstone

Amount of Exposure • Surface area – smaller rocks weather faster • Fractures & joints – natural points of weakness, allows easy breaking

Climate • Hot & cold weather fast • Warm & humid weather fast • Slowest rate – hot, dry

Topograph y& Elevation • Ice wedging & gravity more common in high elevation – its colder • Water carries rock, exposing more rock • Gravity pulls rock down from steep slopes Alps with mountain glacier

Human Activities and Plant & Animal Activities ■ Mining, Construction & Recreation ■ Plants break apart rock ■ Burrowing ■ Bats – Guano – chemical

End of Section 2 Review 1. Explain how rock composition affect the rate or weathering 2. How does the surface area of a rock affect the rate of weathering 3. Identify two ways that climate can affect the rate of weathering 4. Describe two ways that the topography of a region can affect the rate of weathering 5. Summarize 3 ways that human actions can affect t he rate of weathering 6. Explain two ways that animas can affect the rate of weathering 7. Imagine that there is an area of land where mechanical weathering has cause damage. Describe 2 ways to reduce the rate of mechanical weathering