Coastal landscape development Flashcards
How are wave cut platforms formed?
The sea attacks the base of the cliff. A wave cut notch is formed by erosional processes such as abrasion and hydraulic action. As the cliff weakens it falls leading to retreat of the cliff face. The backwash carries away the eroded material leading to a wave cut platform.
How are cave, arches, stacks and stumps formed?
Cracks are widened in the headland through erosional process such as hydraulic action and abrasion. As the waves grind away at the crack it begins to open up to form a cave. The cave then becomes large and forms an arch. The arch becomes larger until the roof of the cliff becomes too weak and collapses leaving a stack. The stack is undercut at the base to form a stump.
What is a barrier beach?
elongated bank of deposited sand parallel to the coastline and not submerged by tides. Where the bank is high enough for dunes to develop it is called a barrier island.
How is a spit formed?
Sediment is carried by longshore drift. When there is a change in deposition a long thin ridge of material is deposited. A hooked end forms then there is a change in wind direction.
What is eustatic sea level change
a global change in sea level resulting from an actual fall or rise in the level of sea itself
What is isostatic sea level change
local changes in sea level change resulting from the land rising or falling relative to the sea
Sea level change 10,000 years ago
sea levels have been rising consistently over the past 10,000 years
20,000 years ago sea levels were 100 - 150m lower
How to changes in sea level occur
increases in the volume of the ocean
subsidence of the coast
How does the volume of the ocean increase
the earths climate warms and ice melts into the ocean.
There is thermal expansion of the ocean
What are bad effects of rising sea levels?
coastal flooding and erosion
