Earth Science, 10th edition

Chapter 3: Weathering, Soil, and Mass Wasting

 

 

    I. Earth's external processes include

    

 

 

  II.  Weathering

       A. Two kinds of weathering

             1. Mechanical weathering

                  

 

             2. Chemical weathering

                  

 

       B. Rates of weathering

             1. Advanced mechanical weathering aids chemical weathering by increasing the surface area

             2. Important factors are

                  a. Rock characteristics

                       

 

                  b. Climate

                       

 

             3. Differential weathering

                  

 

 

III. Soil

       A. An interface in the Earth system

       B. A combination of mineral matter, water, and air – that portion of the regolith (rock

             and mineral fragments) that supports the growth of plants

       C. Soil texture and structure

             1. Texture

                  

 

             2. Structure

              

 

       D. Controls of soil formation

             1. Parent material

                  

             2. Time

                  

 

             3. Climate

 

             4. Plants and animals

                   

 

             5. Slope

                  

 

       E. Soil Profile

             1. Soil forming processes operate from the surface downward

             2. Horizons – zones or layers of soil

                  

 

        F. Soil types

             1. Hundreds of soil types worldwide

             2. Three very generic types

                  a. Pedalfer

                       

 

                  b. Pedocal

                  

 

                  c. Laterite

                       

 

       G. Soil Erosion

 

             1. Recycling of Earth materials

 

             2. Natural rates of erosion depend on

                  

 

             3. Soil erosion and sedimentation can cause

                  

 

 

IV. Weathering creates ore deposits

 

       A. Process called secondary enrichment

              

 

         

 

  V. Mass Wasting

 

       A. The downslope movement of rock, regolith, and soil under the direct influence of gravity

         

       B. Gravity is the controlling force

 

       C. Important triggering factors are

              

       D. Types of mass wasting processes

             1. Generally each type is defined by

                  a. The material involved

                       

                  b. The movement of the material

                       

                  c. The rate of the movement

                       

             2. Forms of mass wasting

                  a. Slump

                       

                  b. Rockslide

                       

                  c. Debris flow (mudflow)

              

                  d. Earthflow

                       

                  e. Creep

                       

                  f. Solifluction

                       

 

 

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