Coasts Flashcards
Coastline
Where the land meets the sea
Factors affecting the coastline
- Power of the waves breaking on the coast
- Coast geology
- Human activity at the coast
Factors impacting the power of waves
- Strength of wind (wind speed)
- Time wind has been blowing
- Distance of water over which the wind blows (fetch)
Types of waves
- Constructive: swash > backwash
- Destructive: swash < backwash
Erosion
the wearing away of rock, stones and soil by waves
Deposition
the dropping of sediment that was being carried by waves
Transportation
the movement of sediment along a coastline, done by the process of longshore drift
Weathering
the decomposition of Earth’s rocks, soils, and minerals in situ through direct contact with the planet’s atmosphere or natural organisms
Mass movement
the movement of material down a slope or cliff due to gravity
Types of weathering
Chemical - carbonates in limestone are dissolved by weak acids in rainwater
Physical/mechanical - Freeze-thaw: water that gets into cracks in rocks turns into ice and expands as temperatures drop, which puts pressure on the rock
Biological - 1. Seeds fall into cracks in rocks and the roots young plants put out can force their way into cracks and break them up. 2. Burrowing animals
Types of mass movement
Rockfall - bits of rock fall off the cliff face due to freeze-thaw
Mudflow - saturated soil flows down a slope
Landslide - large blocks of rock slide downhill
Rotational slip - saturated soil slumps down a curved surface
Landform
a natural feature of the earth’s surface
Headland
an area of more resistant rock that sticks out into the sea
Bay
an area of softer rock that is eroded quickly by wave action
Concordant and discordant coastlines
concordant: strata parallel to the sea
made up of the same type of rock
discordant: strata at right angle to sea
made up of alternating bands of hard and soft rock
Cliff
A steep rock face where the land meets the sea
Sedimentary rock
made up of small particles of sand and rock, which have been transported by the wind, rivers and ice and are usually deposited on lake or seabed
Spit
a long narrow stretch of pebbles and sand which is attached to the land at one end, with the other end extending into the sea
Coral reef
large calcium carbonate deposits created by colonies of small animals called polyps which take up to 10,000 years to form
Coastal management
resolving conflicts at the coast while also protecting areas at risk of flooding and erosion
Types of engineering
soft engineering: works with natural processes
hard engineering: involves the using of artificial structures and major construction
Types of erosion
- Hydraulic action - crashing waves along a cliff’s base force air and water into the cracks
- Abrasion - when material hurled at the base of a cliff wear the surface away
- Attrition - when materials collide, fragments break off, becoming smaller, rounder, and smoother
- Corrosion - chemical reaction between seawater and some types of rock
