The Student Room Group

Aqa geography formations thread

Please can everyone comment ANY formations (describe the processes/steps) they know from :

The restless earth (fold mountains, super volcanos etc)
Water on land (levees, flood plain, meanders etc)
The coastal zone (wave-cut platforms, spits etc)
Coasts:

Wave-cut platform: Destructive waves erode the base of a cliff, forming a wave-cut notch which increases in size through continued erosion. The top of the cliff is weakened through chemical weathering, physical weathering and biological weathering alongside human activity. The cliff eventually collapses a sit cannot support it's own weight. The backwash of destructive waves removes the wreckage, although the densest material is deposited, forming a wave-cut platform. the process retreats and the cliff retreats.

Sea stump: A crack opens in a headland due to erosion. Continued erosion causes the crack to expand and become a cave. Further erosion causes the cave to erode through the headland, forming an arch. Destructive waves erode the base of the arch and the top of the arch is weathered. The arch collapses, forming a sea stack. The stack is also eroded and weathered, causing it to collapse and form a sea stump.

Headlands and Bays: There are alternating bands of hard and soft rock in a cliff face. The soft rock is quickly eroded, causing it to retreat and form a sheltered area which becomes a bay. Constructive waves deposit sediment and build up the bay. The cliff is now a headland protruding out to sea which is vulnerable to erosion.

Beach: The strong swash of constructive waves deposits sediment on a coastline. The heaviest material is deposited first and is located near the cliffs and the lightest material is deposited last and is located near the water.

Spit: Longshore drift moves sediment along a coastline. The swash of constructive waves deposits material at the angle of the prevailing wind and the backwash removes material at a 90 degree angle due to gravity. The coastline eventually comes to an end when it changes direction. Longshore drift continues to deposit sediment out to sea, forming a spit which develops a curved end due to a change in wind direction. A sheltered area forms behind the spit where waves cannot reach, which becomes a salt marsh through deposition of silt.

Bar: Longshore drift moves sediment along a coastline. The swash of constructive waves deposits material at the angle of the prevailing wind and the backwash removes material at a 90 degree angle due to gravity. Longshore drift continues to deposit sediment across a bay and joins two headlands together, cutting off a bay. This forms a bar. The cut off bay forms a lagoon.

Water on the Land:

Waterfall (can be referred to as a gorge) A layer of hard rock lies over a layer of soft rock. The soft rock is quickly eroded, leaving an overhang of hard rock which collapses as it cannot support it's own weight. The collapsed hard rock erodes the river bed, forming a plunge pool. The plunge pool is deepened through further erosion. The process repeats, causing the waterfall to retreat. As water continues downstream, it can encounter further layers of hard and soft rock. The soft rock is eroded, forming rapids.

Oxbow lake: Erosion is fastest on the outside bend of a river. Erosion makes the river neck narrow. Eventually, during times of flooding, the river will take the shortest course and cut through the neck. A new straighter river course is formed and the meander left behind becomes isolated and is now an oxbow lake.

Floodplain: Lateral erosion creates a plain. The river floods. Water slows down due to friction. The densest sediment is deposited closest to the river. The coarsest sediment is deposited further away from the river. Continued flooding, causes sediment to cover the entire plain. A floodplain has been formed.

Levees: The river floods onto the floodplain. Water slows down due to friction. The densest sediment is deposited on the edge of the floodplain but the coarsest sediment is carried further onto the floodplain. Continued flooding causes the sediment to build up, forming levees which act as a natural flood defence.


Restless Earth:

Fold mountains: There is tectonic plate movement on a collision plate boundary. An area of sea separates two plates. Rivers deposit sediment in the geosyncline. Tectonic plate movement compresses the sediment into sedimentary rock. The plates force the rock upwards, forming a series of fold mountains which are elevated above sea level.


Supervolcanoes (supposedly on the specification but here it is just in case) At a hotspot in the Earth's crust, magma collects under the lower crust. A bulge forms as the magma chamber enlarges. Pressure causes cracks to appear at the surface of the crust. Gas and ash erupt through these cracks. The magma chamber eventually collapses, forming a caldera.

Tsunami: Two tectonic plates move towards each other on a destructive plate boundary. The oceanic plate subducts beneath the continental plate as it is denser. The two plates snag, building up pressure. The pressure is eventually released, sending seismic waves through the Earth and causing a violent earthquake. The sea bed is forced upwards as a result. Large ripples are created, travelling across the sea at high speed. As waves approach the shore, the front of the wave slows down but the back continues to travel at high speed. As a result, the wave compresses and it's height increases. A tsunami has been formed.

I hope your exam goes well :smile:
Reply 2
This is amazing!!! Thank you!!
Original post by Cameron_Brown
Coasts:

Wave-cut platform: Destructive waves erode the base of a cliff, forming a wave-cut notch which increases in size through continued erosion. The top of the cliff is weakened through chemical weathering, physical weathering and biological weathering alongside human activity. The cliff eventually collapses a sit cannot support it's own weight. The backwash of destructive waves removes the wreckage, although the densest material is deposited, forming a wave-cut platform. the process retreats and the cliff retreats.

Sea stump: A crack opens in a headland due to erosion. Continued erosion causes the crack to expand and become a cave. Further erosion causes the cave to erode through the headland, forming an arch. Destructive waves erode the base of the arch and the top of the arch is weathered. The arch collapses, forming a sea stack. The stack is also eroded and weathered, causing it to collapse and form a sea stump.

Headlands and Bays: There are alternating bands of hard and soft rock in a cliff face. The soft rock is quickly eroded, causing it to retreat and form a sheltered area which becomes a bay. Constructive waves deposit sediment and build up the bay. The cliff is now a headland protruding out to sea which is vulnerable to erosion.

Beach: The strong swash of constructive waves deposits sediment on a coastline. The heaviest material is deposited first and is located near the cliffs and the lightest material is deposited last and is located near the water.

Spit: Longshore drift moves sediment along a coastline. The swash of constructive waves deposits material at the angle of the prevailing wind and the backwash removes material at a 90 degree angle due to gravity. The coastline eventually comes to an end when it changes direction. Longshore drift continues to deposit sediment out to sea, forming a spit which develops a curved end due to a change in wind direction. A sheltered area forms behind the spit where waves cannot reach, which becomes a salt marsh through deposition of silt.

Bar: Longshore drift moves sediment along a coastline. The swash of constructive waves deposits material at the angle of the prevailing wind and the backwash removes material at a 90 degree angle due to gravity. Longshore drift continues to deposit sediment across a bay and joins two headlands together, cutting off a bay. This forms a bar. The cut off bay forms a lagoon.

Water on the Land:

Waterfall (can be referred to as a gorge) A layer of hard rock lies over a layer of soft rock. The soft rock is quickly eroded, leaving an overhang of hard rock which collapses as it cannot support it's own weight. The collapsed hard rock erodes the river bed, forming a plunge pool. The plunge pool is deepened through further erosion. The process repeats, causing the waterfall to retreat. As water continues downstream, it can encounter further layers of hard and soft rock. The soft rock is eroded, forming rapids.

Oxbow lake: Erosion is fastest on the outside bend of a river. Erosion makes the river neck narrow. Eventually, during times of flooding, the river will take the shortest course and cut through the neck. A new straighter river course is formed and the meander left behind becomes isolated and is now an oxbow lake.

Floodplain: Lateral erosion creates a plain. The river floods. Water slows down due to friction. The densest sediment is deposited closest to the river. The coarsest sediment is deposited further away from the river. Continued flooding, causes sediment to cover the entire plain. A floodplain has been formed.

Levees: The river floods onto the floodplain. Water slows down due to friction. The densest sediment is deposited on the edge of the floodplain but the coarsest sediment is carried further onto the floodplain. Continued flooding causes the sediment to build up, forming levees which act as a natural flood defence.


Restless Earth:

Fold mountains: There is tectonic plate movement on a collision plate boundary. An area of sea separates two plates. Rivers deposit sediment in the geosyncline. Tectonic plate movement compresses the sediment into sedimentary rock. The plates force the rock upwards, forming a series of fold mountains which are elevated above sea level.


Supervolcanoes (supposedly on the specification but here it is just in case) At a hotspot in the Earth's crust, magma collects under the lower crust. A bulge forms as the magma chamber enlarges. Pressure causes cracks to appear at the surface of the crust. Gas and ash erupt through these cracks. The magma chamber eventually collapses, forming a caldera.

Tsunami: Two tectonic plates move towards each other on a destructive plate boundary. The oceanic plate subducts beneath the continental plate as it is denser. The two plates snag, building up pressure. The pressure is eventually released, sending seismic waves through the Earth and causing a violent earthquake. The sea bed is forced upwards as a result. Large ripples are created, travelling across the sea at high speed. As waves approach the shore, the front of the wave slows down but the back continues to travel at high speed. As a result, the wave compresses and it's height increases. A tsunami has been formed.

I hope your exam goes well :smile:

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