Corrosion & Corrasion
Geography: Cambridge International GCSE (2027 Exams), topic 2.1.2
Coastal Erosion Processes: Corrosion and Corrasion
Corrosion and corrasion erode coasts by chemical reactions and mechanical scraping, shaping coastal landscapes through the action of waves and materials.
Coastal erosion processes
- Coastal erosion changes shorelines by wearing away rock and sediment.
- The main physical processes in coastal erosion include corrosion and corrasion.
- Coastal erosion shapes coastal landscapes and affects human activity.
- Understanding these processes helps explain coastal features and hazards.
Corrosion
- Corrosion, or solution, involves chemical action on rock by seawater.
- Coastal erosion by corrosion occurs when acids in seawater dissolve minerals.
- Lime-rich rocks like chalk and limestone are especially affected by corrosion.
- Corrosion weakens rocks, making them more vulnerable to other erosion processes.
How corrosion occurs in coastal erosion
- Seawater contains weak acids like carbonic acid formed from CO2 and water.
- These acids react with calcium carbonate in rocks to dissolve them slowly.
- Coastal erosion by corrosion often forms features like caves and rock pools.
- Corrosion is continuous but slow, acting alongside other coastal erosion processes.
Corrasion
- Corrasion, or abrasion, is the mechanical scraping of the coast by rock fragments.
- Coastal erosion by corrasion occurs when waves hurl pebbles and sand against cliffs.
- Coastal erosion from corrasion wears down rock surfaces and cliff faces physically.
- Corrasion shapes cliffs and beach profiles by grinding down exposed surfaces.
Role of corrosion and corrasion
- Coastal erosion is more effective when corrosion weakens rocks first.
- After corrosion weakens rocks, corrasion then removes these weakened rock particles, deepening erosion.
- Coastal erosion shapes landforms like cliffs, caves, arches, and stacks by these combined actions.
- Both corrosion and corrasion are key components of the physical processes shaping coasts.
Test yourself on Corrosion & Corrasion
How do coastal erosion processes primarily impact human settlements?
Which rock types are most vulnerable to coastal corrosion processes?