Overview:
- Coasts are areas of land that interact with the sea
- They are different due to the variety of terrestrial (land), and marine (sea) environment.
- Coast examples: rocky, sandy, estuarine, coral reef, sand dunes, arctic, high and low energy, bay coasts.
- Vary due to many processes such as geology of land, climate, waves, sediment movement, erosion rates, human management, and the shape of the coastline.
The
Littoral (Sediment) Zone:
- T he coastal area from slightly inland to the same distance out to the ocean
- Big variety of shores
- Dominated by marine processes: Marine is salt water such as sea/ocean, estuaries, tides, waves, sediment movement, erosion and ecology.
- Changes rapidly over time. Short terms – tide storms. Long-term is seasons and ice ages.
- Littoral zone is one of dynamic equilibrium where is are a range of sediments, weathering, mass movement.
Classifying
Coasts:
- Coasts can be put into categories according to the length of time the process takes.
- Long-term: Coast classification (millions of years)
- By geology: sand, cliffs, estuaries and hard or soft rock. Rocks of the same type can be used to classify or ones of similar resistance.
- By sea-level change: Rias, where the sea has risen and flooded the coastal areas (sub-emergent) on raised beaches where the land has risen out of the sea (emergent). World’s oceans were much lower in the Ice Age as water was stored in glaciers and ice caps.
Waves,
Tides & Rivers:
- Coasts can be classified by size/frequency/power of waves which are high or low energy.
- Tides can be measured using tidal range, height from low to high energy every 12 hours.
- Rivers entering coastal waters creates estuaries where fluvial freshwater mixes with salty marine water known as estuarine coasts which aren’t as common as normal coasts.