2b- high energy and low energy Flashcards
key physical factors influencing high energy coastline (geology)
geology- in the south there is a large chalk headland which is harder rock (0.1m/yr) forming Flamborough head. The geology is discordantly lay which allows bays and headlands to form.
key physical factors influencing high energy coastline (wave energy)
Wave energy- there is a 1500km fetch and the winds come from the North, therefore the waves are high energy and mostly destructive, LSD moves sediment south. Wind and waves varies seasonally, in winter and storms higher energy so more destructive. When waves and wind energy is low there will be low levels of erosion and little change to landforms
4 key landforms in high energy coastline
Flamborough head- large chalk headland with an arch and stack and wave cut platform. Wave refraction concentrates wave energy on the headland forming arches and stacks
Robin hoods bay- There is a shore platform there- scars are visible at low tide which represents the different rates of erosion. Headlands on either side are harder rocks that are more resistant to erosion.
Filey bay- accumulates sediment especially in summer due to constructive waves depositing sediment, LSD moves it from north to south
Filey brigg- headland which protects filey bay from destructive waves and winds they loose energy on the headland due to wave refraction and lower energy constructive waves go into the bay. The destructive waves form stacks, arches and caves etc
Landforms into related in a high energy coast line (flamborough head and green stacks)
the wave refraction has meant waves are concentrated on Flamborough head so cracks are attacked by hydraulic action forming caves and arches over time they have formed green stacks pinnacle.
Landforms into related in a high energy coast line (robin hood bay and ness point)
ness point receives the high energy waves from the north that is destructive and so the waves going into the bay are low-energy constructive waves - prevents the bay from being destroyed and allows it to build up (same at filey brigg and filey bay)
how could the landforms change over time in a high energy coastline (flamborough head)
Flamborough head- erosion over time will lead to wave cut notch and cliff collapse so cliff position will change in seconds/minutes. Erosion will happen more extensively in winter.
how could the landforms change over time in a high energy coastline (green stacks)
Green stacks pinnacle- stack will collapse forming a stump after years of erosion, most likely during a winter storm
how could the landforms change over time in a high energy coastline (robin hoods/filey bay )
Filey/Robin Hoods bay- accumulates sediment in the summer and loses it in the winter due to destructive waves. dynamic equilibrium keeps the beach roughly the same size. As headlands erode due to wave refraction more destructive waves will reach the bays
key physical factors influencing a low-energy coastline (fluvial)
Fluvial- two distributaries (Rosetta and Damietta) of the river Nile are the main sources of sediment, as the Nile is split it has less energy so more deposition occurs.
key physical factors influencing a low-energy coastline (wave energy)
Wave energy- LSD occurs from west to east do there are drift-aligned beaches, spits and barrier bars.
key land forms of a low energy coastline
Lake Manzala- the largest lagoon in Egypt.
Damietta onshore bar- formed lake Manzala.
Sabkhas- LSD forms bars across a lagoon. when the water evaporates salt flats (Sabkhas) are formed.
Gamsa sand dues
how the landforms in a low energy coastline could be interrelated
The Damietta on-shore bar cuts off the Manzala lagoon and protects it from the sea and keeps the water still which are the perfect conditions for sabkhas to form.
Sediment from the crescentic bars at Alexandria originally came from the distributaries to form the bar, sediment was moved by aeolian processes to form Gamsa sand dune
how could the landscape change over time in a low energy coastline (Damn)
the Aswan damn is restricting the sediment supply to on-shore bars (Damietta and Rosetta) so they won’t get bigger. The damn also means that less sediment will get to the crescentic bars at Alexandria.
how could the landscape change over time in a low energy coastline (climate change)
due to the rising sea levels, the bars may be breached and sediment may be lost to aeolian processes as its dries quicker so is lighter. Lagoons may become smaller as some sediment from bars is blown into them. As sea levels rise the lagoons could flood.
how could the landscape change over time in a low energy coastline (seasonal)
In the winter winds blow to the west but in the summer they blow to the east so sediment is moved differently throughout the year.
