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Aim : What factors determine the rate of weathering?

Aim : What factors determine the rate of weathering?. I. Rate of weathering factors. A. Rock composition. 1. Igneous and metamorphic rocks do not weather easily. 2. Rocks containing the mineral quartz do not weather easily.

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Aim : What factors determine the rate of weathering?

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  1. Aim: What factors determine the rate of weathering? I. Rate of weathering factors A. Rock composition 1. Igneous and metamorphic rocks do not weather easily 2. Rocks containing the mineral quartz do not weather easily 3. Among sedimentary rocks, limestone and other rocks containing calcite are most easily weathered

  2. Rocks with harder minerals weather slower than rocks with softer minerals 4. The rate at which sedimentary rocks that are weathered by mechanical processes are dependent upon the cementing material a. Shales and sandstones are not firmly cemented together and weather easily and break up into clay and sand particles b. Conglomerates and those sandstones that are strongly cemented by silicates may resist weathering processes for a long time.

  3. Conglomerate

  4. B. Amount of exposure 1. The greater the surface area, the greater the rate of weathering (direct relationship) a. Fractures and joints increase the surface area http://www.classzone.com/books/earth_science/terc/content/visualizations/es1201/es1201page01.cfm?chapter_no=visualization C. Climate 1. Rainfall and the freezing and thawing produced by alternating hot and cold weather have the greatest effect on the rate of weathering

  5. Increased Surface Area

  6. 2. Cold and moist climates increase mechanical weathering 3. Warm and moist climates chemical weathering is dominant • In general, the more moisture available, the more weathering occurs

  7. D. Topography 1. It is colder at high elevations increasing ice wedging 2. Steep slopes have weathered rocks pulled down by gravity and washed away by heavy rains. a. This exposes fresh mountain surface to be weathered.

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