Enquiry Questions 1 and 2: Processes and Landforms Flashcards
beach system
input - sediment from longshore drift. Throughput/transfer - longshore drift.
Output - longshore drift and destructive waves.
Cliff System
Input - sub-aerial weathering.
Throughput/transfer - mass movement and slumping.
Output - removal of material at base of cliff.
Mass movement
The movement of surface material, or a cliff, caused by gravity, but assisted by sub-aerial processes.
Sediment Cell
Areas of coast usually defined by headlands within which marine processes are largely confined with limited transfer of sediment from one cell to another.
Dynamic Equilibrium
The constantly changing nature of the relationship between erosion and deposition. The coastal system is designed so that (in theory) erosion is equal to the amount of deposition occurring.
Destructive Waves
Higher energy. Backwash is more powerful than swash, leading to removal of beach material. Break with great force over a short distance. Short wavelength. Higher wave height. Higher frequency 13-15 waves per minute.
Constructive Waves
Lower energy. Swash is more powerful than backwash, leading to deposition. Break gently over a longer distance. Long wavelength. Low in height. Low frequency 6-8 waves per minute.
Abrasion
The processes of scraping or wearing something away.
Corrosion
The process of materiel being dissolved/corroded by weak acids in the water.
Attrition
Material is eroded and made rounder by hitting against each other.
Hydraulic Action
Air may become trapped in joints and cracks on a cliff face. When a wave breaks, the trapped air is compressed which weakens the cliff and causes erosion.
Sub-aerial weathering
Physical, biological and chemical processes that work to break down rock material.
Freeze Thaw
Freeze thaw weathering involves water entering cracks in rocks and freezing. When the water freezes it expands, fracturing the rock.
Biological weathering
The action of tree roots spreading or rabbits burrowing through the soil in cliffs weakens the structure of the cliffs, leaving it vulnerable to be broken down by other processes.
Hydrolysis
A form of chemical weathering where elements/minerals react with water and weaken the structure of rock over time.
Solution
A form of chemical weathering where rock material is dissolved by weak acids in the water.
Carbonation
Similar to solution, but limestone is weathered by rainwater containing dissolved CO2 (carbonic acid).
Cliff
A vertical rock exposure. They are formed as erosional landforms due to the processes of erosion and sub-aerial weathering.
Wave Cut Platform
The flat area found at the base of a sea cliff that was created by the erosion of waves (wave cut notch and undercutting of overhanging cliff material). They are most obvious at low tide.
Cave
Formed when marine processes (such as hydraulic pressure) attack cracks or joints in the rock. These cracks become larger over time, and continual erosion creates this landform.
Arch
When continual erosion of a cave erodes through the cliff/headland, leaving rock material above.
Stack
When sub-aerial processes attack the overarching rock material over an arch. Once this material has been weakened it will collapse, leaving this landform.