practice 4 mark questions Flashcards
Outline the processes which lead to the development of barrier beaches. (4 Marks)
Barrier beaches are long, narrow islands of sand and shingle which run parallel to the chore but is detached from it.
They form in areas where there’s good supply of sediment, a gentle slope offshore and fairly powerful waves with a small tidal range.
There is debate as to how they form but the most likely theory is that they were bars detached from the coast and were eroded in sections which led to breaches in the bar leading to the island.
Lagoons or marshes often form behind the barrier island where the coast is sheltered from wave action.
Outline the process of sub-aerial weathering in the development of coastal landscapes. (4 Marks)
Sub-aerial weathering significantly impacts the development of coastal landscapes, freeze - thaw weathering occurs where temperatures fluctuate above and below freezing, water enters cracks in rocks and freezes, this causes expansion and cracks the rock, this weakens cliff faces and causes rock fall therefore developing coastal landscapes.
Wetting and drying also occurs as a part of sub-aerial weathering, some rocks contain clay, when clay is wet it expands and causes rock fragments to break of cliff faces due to the pressure of the expansion, this impacts the development of headlands and cliff faces.
Distinguish between hard and soft engineering schemes in coastal management. (4 Marks)
Hard engineering schemes involve built structures, sea walls are the most common hard engineering coastal defence, the walls are usually built out of concrete and reflect the waves out to sea, preventing coastal erosion and act as a barrier against flooding, groynes are also an example of hard engineering coastal defences and are usually built out of wood.
Groynes are in effect fences built along the width of the beach at different points to prevent longshore drift. In contrast to this.
Soft engineering defences involve enhancing and supporting natural processes to defend the coast.
They include beach nourishment which is the addition of sediment to beaches which act as a natural barrier to erosion.
Dune regeneration is another example of soft defences and is when sand gets dunes are created or restored but sand stabilisation to allow the dune to act as a barrier between land of value and the sea while encouraging biodiversity
Explain how a headland and bay coastal landscape is formed. (4 Marks)
Headlands and bays are an erosional feature of coastal landscapes.
They develop on discordant coastlines where the bands of geological strata run perpendicular to the coastline, the less resistant rock on the coastline is eroded at a greater rate than the more resistant rock leading to the formation of bays, this occurs until the wave energy is reduced and the erosion rate slows, long shore drift builds up a beach as the eroded material from the less resistant cliff line is deposited.
The headlands remain as the more resistant rock is eroded at a much slower rate
Outline how spits form and develop. (4 Marks)
Spits are an extension of longshore drift, longshore drift transports sediment in the direction of the prevailing wind.
The spit forms as the longshore drift moves sediment over an estuary of a river,
The sediment is gradually extended over the river estuary and overtime it builds up and eventually rises above sea level, this can lead to vegetation also growing on the spit as animals drop seeds in their stool onto the spit, this can stabilise the spit and lead to it becoming more established.
An example of an established spit is on the Holderness coast (Spurn Head) which is a hub of biodiversity.
Outline how coastal submergence can result in a range of landforms. (4 Marks)
Coastal submergence is where the sea submerges (drowns) the existing coastline this can create multiple landforms. Rias are formed in partially submerged river valleys; they have a gentle long and cross - profile.
Fjords are similar to rias but are drowned glacial valleys, they are straight and narrow with steep sides, the Sognefjordan in Norway is 1000m deep in places.
Explain the development of saltmarsh environments. (4 Marks)
Saltmarshes form in sheltered, low energy environments such as behind river estuaries as seen on Morecambe bay.
Silt and mud are deposited by the river or the tide, saltmarshes develop.
Mudflats are then colonised by vegetation that can survive the high levels of salt and long periods of submergence by the tide such as saltwort.
Plants trap more silt and mud and gradually build up to create larger saltmarshes which remain exposed for longer between tides.
Outline the processes which lead to the development of barrier beaches. (4 Marks)
Barrier beaches are long, narrow islands of sand and shingle which run parallel to the chore but is detached from it.
They form in areas where there’s good supply of sediment, a gentle slope offshore and fairly powerful waves with a small tidal range.
There is debate as to how they form but the most likely theory is that they were bars detached from the coast and were eroded in sections which led to breaches in the bar leading to the island.
Lagoons or marshes often form behind the barrier island where the coast is sheltered from wave action.
