Factors Influencing Weathering © Copyright 2007.  M. J. Krech. All rights reserved.

1. Surface Area Surface area increases simply from the subdivision of large blocks into smaller blocks. The greater the surface area, the greater the rate of weathering.

2. Rock Type Differences in the type of rock can lead to different rates of weathering. Sedimentary rocks weather much faster than metamorphic and igneous rocks.

Sandstone vs. Granite

3. Slope Angle On a steep slope, weathered particles move quickly away, continually exposing fresh bedrock to more weathering.

3. Slope Angle On gentle slopes, weathered particles are not easily washed away.

4. Climate Cooler, dryer climates have more mechanical weathering

Hotter, wetter climates have more chemical weathering

4. Climate Rocks such as limestone/dolomite are highly susceptible to chemical weathering in a moist climate and commonly form KARST landscapes. In a dry climate, however, the same rocks form bold cliffs because, with low rainfall and only patchy vegetation, little carbonic acid is present to dissolve the minerals.

5. Burrowing animals Large and small burrowing animals bring rock particles to the surface. Burrowing animals form tunnels which gives water access to deep underground

6. Time Thousands of years are required for an igneous rock to weather. Weathering processes are speeded up by increased temperature and precipitation, and by decreased particle size.

7. Location Rocks located in heavily polluted areas will be much more susceptible to both mechanical and chemical weathering because of the increased occurrence of acid rain caused by factory pollution, car exhaust, etc.

7. Location Of course, rocks located in less poluted areas, far from the pollution of cities, will weather at a much slower rate.

THE END Take a guess: What types of pollution are the rocks in your school’s neighborhood most likely to experience? List on the bottom of your paper for BONUS Points! © Copyright 2007.  M. J. Krech. All rights reserved.