Erosion and Landforms

Erosion Processes

• Hydraulic Action

  • The force of water hitting the riverbank or cliff.
  • Compresses air into cracks, causing material to break off.

• Abrasion (Corrasion)

  • The process where rocks carried by the water scrape against the bed and banks.
  • This leads to the gradual wearing away of these surfaces.

• Attrition

  • Rocks carried by the river or sea collide with one another.
  • Through continuous impact, they break into smaller, smoother pieces.

• Solution (Corrosion)

  • The process in which acids present in water dissolve certain types of rocks.
  • Commonly affects rocks like chalk or limestone.

Transportation Processes

• Traction

  • Large boulders are rolled along the riverbed by the force of water.

• Saltation

  • Small pebbles are bounced along the riverbed in a hopping motion.

• Suspension

  • Fine and light materials are carried along with the flowing water.

• Solution

  • Minerals are dissolved in water and transported within the flow.

Deposition

• Occurs when a river or the sea loses energy, resulting in the dropping of the material it was carrying.

River Landforms

• Meander

  • Describes a bend in a river, typically forming due to erosion and deposition.

• Oxbow Lake

  • A U-shaped lake formed when a meander is cut off from the river.

• Waterfall

  • The point at which a river flows over a vertical drop, creating significant elevation change.

• Floodplain

  • Flat land adjacent to a river, subject to flooding and deposition during high water events.

• Delta

  • A landform found at the mouth of a river, formed by the deposition of sediment carried by the river.

Coastal Landforms

• Headland

  • A prominent high point of land that extends into the sea, often susceptible to wave action.

• Bay

  • A broad inlet of the sea where the land curves inward, often providing sheltered waters.

• Cliff

  • A steep rock face typically found near coastlines, often resulting from erosion.

• Wave-cut Platform

  • The flat area left behind after the erosion of a cliff, often exposed at low tide.

• Arch

  • A hole that is eroded through a headland, typically formed by wave action.

• Stack

  • A pillar of rock left standing after an arch collapses due to continued erosion.

• Stump

  • A small remnant of rock that remains after a stack undergoes further erosion.

Other Key Terms

• Weathering

  • The process of breaking down rocks due to various environmental factors; can be physical, chemical, or biological.

• Mass Movement

  • The downhill movement of rocks and soil caused by gravity, such as landslides.

• Longshore Drift

  • The movement of sediment along a coastline due to wave action, affecting beach morphology and coastal geology.