Coasts Flashcards
List the different zones of the coastal zone from back to front
Backshore:above tide level only affected by waves during high tides
foreshore: where wave processes occur between the high and low tide marks
nearshore: shallow water areas close to land
offshore: open sea
What are the two main types of coasts?
Clifford coastlines with cliffs varying in height from a few metres to hundreds of meters
Coastal plains where the land gently slopes towards the sea across an area of deposited sediment, often in the form of sand dunes and mudflats
What is the difference between primary and secondary coasts?
Primary coasts are dominated by land based processes, such as deposition at the coast from rivers or new coastal land formed from lava flows
Secondary coasts are dominated by marine erosion or deposition processes
How does the wave energy affect the formation of a coast
Low energy makes sheltered coast with limited fetch and low wind speeds resulting in smaller waves
High energy exposed coasts facing prevailing winds with long save fetches resulting in powerful waves
What are coastal plains?
Low lying flat low relief areas
What are the two main cliff profile types?
Marine erosion dominated: wave action dominates and cliffs tend to be steep, unvegetated and there is little rock debris at the base of the cliff
Subaerial process dominated: not actively eroded at the base by waves shallower, curved slope and lower relief; surface runoff and mass movement are responsible for the cliff shape
What are coastal plains?
Low lying flat low relief areas
What are the two main cliff profile types?
Marine erosion dominated: wave action dominates and cliffs tend to be steep, unvegetated and there is little rock debris at the base of the cliff
Subaerial process dominated: not actively eroded at the base by waves shallower, curved slope and lower relief; surface runoff and mass movement are responsible for the cliff shape
What are coastal plains?
Low lying flat low relief areas
How do coastal plains form?
- sea level falls, exposing the sea bed of what was once a shallow continental shelf sea
- sediment brought from the land by river systems is deposited at the coast causing costal accretion so coastlines gradually move seaward
- sediment is moved from offshore sources towards the coast by ocean currents
What are the three elements to geological structure?
What are the free elements to geological structure
Strata: the different layers of rock exposed in a cliff
Deformation: tilting and folding by tectonic activity
Faulting: major fractures that have moved rocks from their original positions
What’s the difference between a concordant and discordant coast?
Concordant is when rock strata run parallel to the coastline
Discordant is when different rock strata intersect the coast at an angle so rock type varies along the coastline
What is a bay?
When the land curves inland
What is a headland?
A point of land usually high and often with a sheer drop that extends out into a body of water.
What are anticyclines and synclines?
Types of geological fold caused by tectonic compression m. Anticlines form crests and synclines form troughs.
