Weathering

Physical Weathering

• Exfoliation: rock breaks apart in layers
  • Igenous rocks
  • Half Dome
  • Stone Mountain, Georgia
• Frost Wedging
  • Shattered rocks
• Biological
• Abrasion: wind, ice, water

Chemical Weathering

• mineral breakdown
• Dissolution (dissolver in water)
• Acid Reactions (water + CO2 carbonic acid); Water + sulfur sulfuric aside
  • H2O + CO2 + CaCO3 –> Ca+2 + 2HCO3-
• Oxidation
• Hydration: attachment of water to crystalline structure
• Hydrolysis: Hydrogen and oxygen in water with rock
• Solution: rock is dissolved in water
  • pH, temperature
  • evaporite deposits
• Goldrich Stability series
  • Similar to Bowen’s Reaction Series but for speed to weather
  • Olivine/pyroxene + H2CO3 (acid) to clay
• Karst landforms
  • limestone sinkhole

Erosion by Gravity

• Rock fall
  • Talus: debris at base of a steep slope
  • Peru, 1970 Nevado Huascaran
• Rock Slides
• Soil Slumps
• Mud flows
• Lahar: 1985 Columbia: 70km!
• Debris flow
• Creep: leaning poles, bent trees

Erosion by water

• Point bar: deposits from water slowing
• Cut Bansk show erosion from fast water
• River meanders
• Oxbow lakes (Australian Billabong)
• Alluvial Fans

Aswan Dam

• 1960 – 1971
• Formed Lake Nassar
• Many economic tenets
• Many ecological/economic costs

Ground Water

• Water cycle
  • Percolation: water seeping into ground water
  • Run off to see
  • Evaporation
  • Condenstations
  • Precipitation
  • Transpiration: water from plants)

Glaciers

• Movement
• Types: Alpine, Continental

Deserts and Wind Action