Coasts Flashcards
How is a wave formed
Friction occurs between air and water. Water particles move in a circular motion. Air pressure and friction creates waves.
What is a sediment cell?
A coastline that is self-contained. Closed system bounded by headlands. There is erosion, deposition and transport of sediment. Inputs from sea , land or river. Human activity can interrupt the distribution.
What is a discordant coastline?
Where the types of rock alternate along the coastline creating headlands and bays
What is a concordant coastline?
Where rocks lie parallel to the coastline
What is a swell?
Swell are waves that originate offshore
What is a neap tide?
When the moon and the sun are at 90 degrees with the earth. The lowest of low tides
What is a spring tide?
A tide just after the full moon, when there is the greatest difference between high and low tide.
What is long-shore drift?
Where waves come in at an angle to the shoreline and retreat perpendicularly
What is mass movement?
The downhill movement of weathered material due to gravity
What is a simple spit?
A straight spit that grows out roughly parallel to the coast
What is a compound spit?
A spit that has multiple recurved hooks , resulting from several periods of growth
What is a sand-bar?
An area of sand that sits above the water, connecting the shoreline
How is a sandbar formed?
A sandbar is formed when a spit grows the whole way across the bay
What is isostatic change?
When the land rises or falls relative to the sea at a local scale
What is eustatic change?
A global change in sea level change resulting from an actual fall or rise in the level of the sea itself
What is a submergent coastline?
Where the ocean has overtaken previously low lying areas
What are the landforms of submergent coastlines?
Rias, Fjords, Estuaries
How are Rias formed?
When rising sea levels flood the lower part of the river valleys.
How are fjords formed?
Created when glaciers retreat and sea levels rise, filling valleys with sea-water.
How are estuaries formed?
Created by rising sea levels flooding river mouths
What is an emergent coastline?
When a fall in sea level exposes land previously covered by the sea
What are the different landforms of emergent coastlines?
Raised Beaches, Marine platforms, caves
How are raised beaches formed?
They form when tectonic forces uplift coastal areas, lifting former shorelines above the reach of the sea
How are marine platforms formed?
They form through the process of erosion, where waves continually pound against the base of coastal cliffs, gradually wearing away
How is a wave cut platforms/wave cut notches formed?
When the sea attacks a weakness at the base of the cliff, causing an undercut
What are the sequences in coastal erosion?
Discordant coastline/Concordant coastline=> Headland=> crack=> cave=> arch=> stack=> stump
What are the types of erosion?
Hydraulic action, abrasion, attrition and solution
What is hydraulic aciton?
When waves hit/pound the shore
What is abrasion?
When pebbles grind along a rock platform, and sediment in waves are thrown against the cliff-face
What is attrition?
Where rocks/materials are carried by water and collide breaking down into smaller pieces
What is solution?
Where rocks are dissolved in water/chemically
What are the types of weathering?
Physical, Chemical , Biological
What is freeze-thaw weathering?
Water enters cracks in rocks, freezes , expands and causes the rock to break apart
What is hydrolysis?
Water reacting with rocks causing it to dissolve
What is a tombola?
a bar of sand or shingle joining an island to the mainland.
What are the 4 types of mass movement?
Rock fall, landslide, mudslide and slumping.
What causes mass movement?
Cliffs being made out of soft rock ( boulder clay) being highly susceptible to erosion and weathering . Also caused by sub-aerial processes such as precipitation
What is a marine platform?
Rock base of eroded cliffs that extends as cliffs retreat
What is isostatic re-adjustment?
When the land rises due to ice melting, which was weighing the land down before
What is a relict cliff?
A relict cliff is an old cliff that used to be at the coastline but is now found inland due to changes in sea level or land uplift
What is an example of a raised beach?
Isle of Arran
How is precession affecting Eustatic change?
Due to sea level changing due to the earth’s rotation, influencing melting of ice and global sea temperatures.
What are the different sub-aerial processes and how do they affect the coastline?
Biological, Chemical and Physical weathering and mass movement
Freeze thaw- weakens cliff faces
Solution- affects clay and mass movement
How are spits made?
LSD moves sediment along the coast, depositing it until the mainland ends to form a spit, which can develop a recurved hook if secondary winds shift the angle of deposition
What is Long-shore drift?
Longshore (littoral) drift is the movement of material along the shore by wave action. It happens when waves approach the beach at an angle
Outline the development of a salt-marsh
Occurs in low lying energy environments/ behind rivers and estuaries. Mud is deposited by river and tide=> Colonised by vegetation=> building up mud / nutrients
Explain how sand dunes are formed?
Sand dunes form when onshore winds transport sand above the high-water mark, where vegetation like marram grass traps and stabilizes the sand, allowing dunes to grow over time, develop richer soils, and support diverse plant species that further anchor and protect the dunes.
What are negative feedback loops within coasts?
(Destructive waves)=> Sediment eroded/ deposited offshore, forming offshore bar, waves break before reaching beach, storm calms, conditions return to dynamic equilibrium
What are positive feedback loops within in coasts?
Groynes/Erosion. Groynes interrupt the sediment supply => Increasing erosion rate.
Erosion can be self-enhancing due to weaking coastal material
What factors affect a coastal landscape?
weathering, transportation, deposition, erosion.
What is a shingle
a mass of small rounded pebbles, especially on a seashore.
What is the role of marram grass in sand dunes?
Marram grass traps sand, stabilizes dunes with deep roots, and helps colonize harsh environments, protecting dunes from erosion.
What are coastal landforms caused by deposition?
bars, spits, beaches
What is a barrier beach?
A barrier beach is a long, narrow, and typically sandy landform that runs parallel to the coastline, separated from the mainland by a body of water such as a lagoon, bay, or estuary
How is a barrier beach formed?
It is formed by the accumulation of sand and sediment due to wave action and longshore drift. Barrier beaches help protect the mainland from storm surges and erosion by absorbing wave energy.
What coastal landscapes are formed by weathering?
Cliffs & wave cut notches, caves , arches , stacks , stumps
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