Transcript Chapters 7 & 8- Erosion, Weathering, Mass Movements

Chapters 7 - Erosion
& Weathering
Lecture 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)