Chapters 7 - Erosion Chapters 7 - Erosion & Weathering& Weathering

Lecture notesLecture notes

• Erosion- removal and transport of weathered materials

•Weathering- process that breaks down or changes rocks on or near Earth’s surface

• Mechanical- breaks rocks and minerals into smaller pieces (physical)– Temperature, and pressure are involved

in physical weathering

– Frost wedging- repeated thawing and freezing of water, causes rocks to split

– Exfoliation- outer rock layers stripped away

                                                                                   

• Chemical weathering- rocks and minerals undergo changes in composition

– Chemical reactions– Rocks with calcite (limestone)– Warmer temperatures, increase

reaction– Water can dissolve many rocks

• Chemical weathering- rocks and minerals undergo changes in composition

–Oxidation- chemical reaction of oxygen with other substances

–Carbon Dioxide contributes

–pH below 5.6 is acidic

• Climate determines rate of weathering–Chemical weathering faster in

warm, wet climates–Physical weathering faster in

cool, dry climates• Type of rock

–Sedimentary weather faster

• Surface area- more area, more weathering

• Topography- slopes have more erosion (gravity)