This topic examines the factors influencing coastal processes and landforms, focusing on the interaction of winds, waves, currents, and sediment supply. It
Topic Synopsis
This topic examines the factors influencing coastal processes and landforms, focusing on the interaction of winds, waves, currents, and sediment supply. It covers lithological and structural geological factors that shape rocky, sandy, and estuarine coastlines within a systems framework.
Key Concepts & Core Principles
- Wave energy and type: Constructive waves (low energy, strong swash) build beaches, while destructive waves (high energy, strong backwash) erode them. Fetch and wind strength determine wave energy.
- Geological structure: Lithology (rock type) and structure (joints, faults, bedding planes) influence erosion rates. Concordant and discordant coastlines produce different landform patterns (e.g., Dalmatian vs. Haff coastlines).
- Tidal range and currents: Macro-tidal coasts (range >4m) have strong tidal currents that transport sediment, affecting estuary morphology and salt marsh development.
- Sediment budget: The balance between sediment inputs (from rivers, cliff erosion) and outputs (longshore drift, offshore loss) determines whether a coastline is eroding, stable, or accreting.
- Human intervention: Hard engineering (e.g., sea walls, groynes) alters sediment transport and can exacerbate erosion elsewhere, while soft engineering (e.g., beach nourishment) works with natural processes.
Exam Tips & Revision Strategies
- Use specific terminology for structural geology (e.g., dip, joints, faulting) rather than generic descriptions.
- Ensure you can explain how wave refraction concentrates energy on headlands.
- Practice linking specific rock types (e.g., limestone vs. clay) to their solubility and resistance to erosion.
- Always relate the factors back to the coastal system (inputs, stores, transfers, outputs).
Common Misconceptions & Mistakes to Avoid
- Confusing wave refraction with wave reflection.
- Failing to link lithological characteristics (e.g., hardness) directly to the rate of erosion.
- Overlooking the role of structural geology (e.g., dip) in determining cliff profiles.
- Treating factors in isolation rather than as interdependent components of a coastal system.
Examiner Marking Points
- Explanation of fetch, wave type, wave orientation, wave refraction, and wave reflection.
- Analysis of lithological factors including mineral composition, hardness, and solubility.
- Description of structural geology features such as bedding, dip, joints, folding, and faulting.
- Application of the systems framework to explain how these factors influence coastal processes and landforms.