- Sub-aerial weatheringthe gradual break down of rock by agents such as ice, salt, plant roots and acids. Weathering weakens cliffs and makes them more vulnerable to
Salt Weathering
- Caused by saline water.
- Enters pores/cracks at high tide.
- Tide goes out, rocks dry and water evaporates, forming salt crystals. As they form, they expand, exerting pressure on the rock causing pieces to break off.
Freeze-thaw Weathering
- Occurs in areas where temperatures fluctuate above and below freezing.
- Water enters the joints and crevices in rocks.
- If the temperature drops below 0C, the water in the cracks freezes and expands.
- Repetition weakens the rocks causing pieces to fall off.
Chemical Weathering
- Breakdown of rock by changing its chemical composition.
Wetting and Drying
- When clay gets wet, it expands, and the pressure caused by this breaks fragments of the rock.
- Mass movement is when material moves down a slope:
- Mass movement – the shifting of material downhill due to gravity.
- Slides- material shifts in a straight line.
- Slumps- material shifts with a rotation.
- Rockfalls- material breaks up and falls.
- Mudflows- material flows downslope.
- Unconsolidatedrocks are prone to collapse as there’s little friction between particles to hold them together.
- Heavy raincan saturate unconsolidated rock, further reducing friction and making it more likely to
- Runoffcan erode fine particles and transport them downslope.