This topic covers the processes of coastal transport and deposition, including the mechanisms of sediment movement and the resulting landforms. It examines
Topic Synopsis
This topic covers the processes of coastal transport and deposition, including the mechanisms of sediment movement and the resulting landforms. It examines how reduced energy levels lead to depositional features and the formation of specific coastal landscapes both within and beyond the UK.
Key Concepts & Core Principles
- Longshore drift: The zigzag movement of sediment along the beach due to waves approaching at an angle, driven by prevailing wind direction.
- Sediment cell: A closed system of sediment transport, erosion, and deposition, with inputs (e.g., cliff erosion) and outputs (e.g., offshore losses).
- Depositional landforms: Features like spits (extending across a bay), tombolos (connecting an island to the mainland), and barrier beaches (offshore ridges) formed by sediment accumulation.
- Swash and backwash: The uprush (swash) and downrush (backwash) of waves; deposition occurs when swash is stronger than backwash, often on constructive waves.
- Sediment sorting: The process by which waves sort sediment by size, with coarser material deposited on the upper beach and finer material lower down.
Exam Tips & Revision Strategies
- Use clear, annotated diagrams to illustrate the formation of landforms like spits and bars
- Ensure you can explain the role of longshore drift in the development of depositional landforms
- Be prepared to provide examples of these landforms from both UK and non-UK contexts
- Use precise terminology for transport processes (e.g., solution, suspension, saltation, traction)
Common Misconceptions & Mistakes to Avoid
- Confusing the specific mechanisms of transport (e.g., saltation vs. traction)
- Failing to link the reduction in energy levels directly to the process of deposition
- Inaccurate description of the formation sequence for complex landforms like spits or tombolos
- Neglecting to mention sediment sorting as a key outcome of depositional processes
Examiner Marking Points
- Processes of coastal transport: solution, suspension, saltation, traction, and longshore drift
- Processes of coastal deposition: reduced energy levels, flocculation, and sediment sorting
- Characteristics and formation of coastal landforms: beaches, spits, bars, tombolos, and cuspate forelands