Erosion and Deposition - Shaping Earth's Landscape
Erosion and Deposition
- Weathering: Breakdown of rocks into smaller particles (sediment).
- Erosion: Transportation of sediment to a new location, mainly by moving water, ice, wind, and animals.
- Deposition: Sediment settles in a new location.
- Cycle: Weathering breaks down, erosion transports, and deposition settles sediment.
Weathering
- Mechanical Weathering: Physically chipping away at rocks.
- Chemical Weathering: Water chemically reacts with rocks, changing their composition.
Agents of Erosion
- Moving Water: Rivers and streams erode sediment.
- Ice and Glaciers: Pick up and deposit rocks and sediment.
- Wind: Moves small sediments like sand.
- Animals (including humans): Activities like burrowing or construction cause erosion.
Factors Affecting Deposition
- Particle Size: Smaller particles settle slower.
- Particle Shape: Round particles settle faster than flat ones.
- Particle Density: Higher density particles settle faster.
- Velocity: Decreasing velocity leads to sediment deposition.
Mass Movement
- Definition: Movement of large amounts of soil and rock down a slope due to gravity.
- Factors: Slope steepness, vegetation cover, groundwater, and climate.
Types of Mass Movement
- Landslides: Quick downhill movement of rock, debris, or soil.
- Mudflow: Rapid downhill flow of mud (rock, soil, and water mixture), common in arid areas.
- Slump: Loosely connected rock and soil move a short distance down a slope, forming a slump block.
- Creep: Slow downhill movement of rock and soil, often indicated by bent trees.
Key Concepts
- Weathering breaks down surface materials into sediment.
- Erosion transports sediment.
- Deposition places sediment in new locations.
Types of Mass Movements
- Landslide: Quick downhill movement of rock and soil; the most devastating.
- Mudflow: Quick downhill movement of a mixture of rock, soil, and water.
- Slump: Sudden downhill movement of a large mass of rock and soil.
- Creep: Slow movement of rock and soil downhill.