Topic Physical and Chemical Weathering. Weathering vs. Erosion Weathering--Erosion--
Weathering and Erosion
description
Transcript of Weathering and Erosion
Weathering and Erosion
AmoleSpectra of Science
2013
Weathering vs. Erosion• They work together,
but are NOT the same thing
• Weathering is a process that breaks down rock
• Erosion is a process that moves rock
Weathering is like the hammer.
Erosion is like the truck.
Types of Weathering• Physical- breaks down rock without
changing its chemical composition– Frost wedging– Plant roots– Wind– Water
• Chemical-breaks down rock by changing its chemical composition– CO2
– Acid Precipitation– Rust
Frost Wedging• Physical Weathering• Water seeps into cracks• Freezes and expands• Pushes rock apart
Root Pry
• Physical Weathering• Plant roots grow into
rock• Pushes rock apart
Wind Abrasion• Physical Weathering• Wind carrying sand blasts against these rocks
causing them to become rounded
Animal Burrows
• Physical Weathering• Animals create tunnels in rock and sediments
breaking them up
Water Abrasion• Physical Weathering• Running water
repeatedly flows over river rocks making them smooth
Oxidation of Iron• Chemical
Weathering
• This rock is red because of the oxidation of iron in the sediment when the rock was being formed
Acid Precipitation• Chemical Weathering• Released gases from
burning fossil fuels react with water in the air to create acids
• This acid reacts with limestone to decompose it
1908 1969
Living Organisms• Lichens that grow on rocks produce weak
acids that chemically weather rock
Water• Chemical Weathering
• Water can dissolve minerals found in rocks
Water• Chemical Weathering
• Water can dissolve minerals found in rocks
Carbon Dioxide• Chemical Weathering
• Reacts with water to form acid
Erosion• Process by which rock is moved or
transported• Deposition- process by which material
(sediments) are laid down
Water Erosion• Water transports and then eventually
deposits sediments• Can create deltas, meanders, canyons, and
flood plains
Meander
• S-shaped streams• Wander side to side seeking lowest elevation
Delta• Occur where rivers
meet the ocean• Soil, dirt, sediments
deposited at river mouth
• Creates new soil-rich land
Canyons
• Large valleys created by rivers or streams over time
• Grand Canyon “cut” by Colorado River
Wind Erosion
• Wind picks up and carries sediments to new locations
• Creates sand dunes
Erosion by Gravity
• Gravity causes large masses off rocks and sediments to move from higher locations to lower ones
• Ex: avalanches, land slides, and mudslides
Erosion by Ice• Glaciers carve U-shaped
valleys as they pick up and carry rock fragments along the way
Weathering and
Erosion QUIZ
Frost Wedging
Physical Weathering
Root Pry
Physical Weathering
Water Erosion
Erosion by Glacier
Erosion by Gravity
Erosion by Gravity
Physical Weathering- Frost WedgingErosion- Wind
Chemical Weathering- Acid Precipitation
The marble grave marker has been attacked by acidic rain because of the calcite composition. The grave marker on the right, while old, has not been dissolved because of its granite composition
Physical Weathering-
Tree Pry
Erosion by Gravity