distinctive landscapes - gcse

What is a Landscape?

Landscapes are made up of all visible features of an area of land.

What is a Natural Landscape?

A landscape with more physical features, such as mountains or forest.

What is a Built Landscape?

A landscape with more visible human features, such as a town or a city.

Where are Upland Areas usually found?

They are mostly found in the north and west of the UK.

Where are Lowland Areas usually found?

They are mostly found in the south and east of the UK.

Where are Glaciated Landscapes usually found?

They are mostly found in upland areas in the north-west of the UK.

What are the Characteristics of Upland Areas?

• They are generally formed of harder rocks which resist erosion, e.g. slate, granite and some limestones.

• Many are glaciated landscapes e.g. Snowdonia

• The gradient of the land is often steep.

• The climate tends to be cooler and wetter.

• The harsh climate and thin soils allow rough vegetation to thrive, and some upland areas are used for forestry.

• Land uses include sheep farming, quarrying and tourism.

What are the Characteristics of Lowland Areas?

• They are generally formed from softer rocks, e.g. chalk, clay and some sandstones.

• The landscape is flatter with gently rolling hills.

• The climate tends to be warmer and drier.

• Vegetation grows easily in the more fertile soils and includes greasy meadows and deciduous forests.

• Land uses include quarrying and tourism, as well as dairy and arable farming (growing crops).

• Most urban areas and industries (e.g. factories) are located in lowland areas.

What are the Characteristics of Glaciated Landscapes?

• Ice is very powerful, so it was able to erode the landscape, carving out valleys. It also deposited lots of material as it melted.

• Landscapes formed by glacial meltwater and deposits extend south of this line.

What is Mechanical Weathering?

The breakdown of rock without changing its chemical composition.

What is Chemical Weathering?

The breakdown of rock by changing its chemical composition.

What is Biological Weathering?

The breakdown of rocks by living things e.g. plant roots break down rocks by growing into cracks on their surfaces and pushing them apart.

What is Mass Movement?

Mass movement is the shifting of rocks and loose material down a slope, e.g. a cliff or valley side. It happens when the force of gravity acting on a slope is greater than the force supporting it. Mass movements cause coasts to retreat rapidly. They're more likely to happen when the material is full of water - it acts as a lubricant and makes the material heavier.

What are the two types of Mass Movement?

• Slides; material shifts in a straight line

• Slumps; material shifts with a rotation

What are the four processes of Erosion?

1. Hydraulic Action

2. Abrasion

3. Attrition

4. Solution

What is Hydraulic Action?

Along coasts, waves crash against rock and compress the air in the cracks. This puts pressure on the rock. Repeated compression widens the cracks and makes bits of rock break off. In rivers, the force of the water breaks rock particles away from the river channel.

What is Abrasion?

Eroded particles in the water scrape and rub against rock in the sea bed. cliffs or river channel, removing small pieces and wearing them away. Most erosion in rivers happens by abrasion.

What is Attrition?

Eroded particles in the water smash into each other and break into smaller fragments. Their edges also get rounded off as they rub together. The further material travels, the more eroded it gets.

What is Solution?

Dissolved carbon dioxide makes river and sea water slightly acidic. The acid reacts chemically with some rocks.

What are the four processes of transportation?

1. Traction

2. Saltation

3. Suspension

4. Solution

What is Traction?

Large particles like boulders are pushed along the river bed or sea floor by the force of the water.

What is Saltation?

Pebble sized particles are bounced along the river bed or sea bed by the force of the water.

What is Suspension?

Small particles like silt and clay are carried along by the water.

What is Solution?

Soluble materials dissolve in the water and are carried along.

What is Deposition?

Deposition is when material being carried by sea water or a river is dropped. It occurs when water carrying sediment loses velocity so that it isn't moving fast enough to carry so much sediment.

What are Constructive Waves?

Constructive waves have a low frequency (6-8 waves per minute)

What are Destructive Waves?

Destructive waves have a high frequency (13-15 waves per minute)

What causes Coastal Deposition?

• There's lots of erosion elsewhere on the coast, so there's lots of material available.

• There's lots of transportation of material into the area.

What causes River Deposition?

• The volume of water in the river falls

• The amount of eroded material in the water increases

• The water is shallower, e.g. on the inside of a bend

• The river reaches the sea or a lake at its mouth

What causes Headbands and Bays?

Headbands and Bays form where there are alternating bands of resistant and less resistant rock along a coast.

How do Headbands and Bays form?

• Differential erosion occurs as more resistant (harder) rock erodes slower than the less resistant rock.

• As the less resistant rock is eroded away quicker it creates a bay leaving the more resistant rock jutting out into the sea as headlands.

How are Caves formed?

• Headlands are usually made of more resistant rocks that have weaknesses like cracks.

• Waves crash into the headlands due to wave refraction and enlarge the cracks mainly by hydraulic action and abrasion.

• Repeated erosion and enlargement of the cracks causes a cave to form.

How are Arches formed?

Continued erosion deepens the cave until it breaks through the headland forming an arch.

How are Stacks formed?

• Erosion continues to wear away the base of the arch and weathering weakens the roof.

• The arch eventually collapses to form a stack - an isolated rock that separate from the headland

How are Beaches formed?

• Beaches are formed by constructive waves depositing material which has often been eroded further along the coast and transported by longshore drift.

What are the Characteristics of Sand Beaches?

Sand beaches are flat and wide - sand particles are small, and the weak backwash can move them back down the beach, creating a long, gentle slope.

What are the Characteristics of Shingle Beaches?

Shingle beaches are steep and narrow - shingle particles are large, and the weak backwash can't move them back down the beach. The shingle particles build up to create a steep slope.

What are Spits?

Spits are beaches that stick out into the sea - they're joined to the coast at one end. Spits form at sharp bends in the coastline, e.g. at a river mouth.

What causes Spits to form?

• Spits from where there is a sharp change in the direction of the coastline e.g. at a river estuary.

• Longshore drift transports material along the coastline and past the bend. Then deposits it in the sea as the wave's loose energy in the deeper water.

• This process repeats and the spit gets bigger over time.

• Changes in the direction of the wind can cause the spit to become curved at the end (a hook).

• The spit won't grow across the whole river estuary due to the river current flowing out into the sea.

• Behind the spit a saltmarsh is created as the area is protected from the waves and plants start to grow there.

What is a River Basin?

An area of land surrounding a river, where any rain falling on the land eventually makes its way into the river. This area is also called a river's catchment.

What is a Tributary?

A river or stream flowing into a larger river or lake.

What is the Mouth of a River?

Where a river flows into the sea or a lake.

What causes V-Shaped Valleys?

In the upper course of the river, the river cuts rapidly downwards, as the main direction of erosion is vertical. This causes the most distinctive river feature, the V-shaped valley. Freeze-thaw weathering and other processes create loose material on the valley sides which are then washed into the river from the steep valley sides during times of heavy rainfall, adding to the material being carried by the river. This means that abrasion can continue to steepen the valley and the river cuts further downwards.

What causes Waterfalls to form?

When a river flows over alternating layers of hard/soft rocks waterfalls can be formed. As the river flows over the hard rock onto soft rock, the soft rock will be more easily eroded. A plunge pool is created and processes such as abrasion and hydraulic action cause further erosion of the soft, less resistant, rock. Over time this creates an overhang which eventually, due to gravity, collapses under its own weight.

What causes Gorges?

The process to form waterfalls happens repeatedly which means that the waterfall gradually retreats upstream creating a gorge.

What are Meanders?

Meanders are bends in the river.

What causes Meanders?

They are formed by a combination of erosion and deposition. The faster water travels around the outside of the bend, eroding the banks through abrasion and hydraulic action. This creates a steep river cliff. On the inside of the bend the velocity is much slower and consequently, deposition occurs creating a slip-off slope.

What causes an Ox-Bow Lake?

Over time the meander becomes more pronounced and the 'neck' of the meander becomes smaller. Eventually the river will break through the neck of the meander to create a new, straighter channel and an ox-bow lake will remain.

What is a Floodplain?

The floodplain is a wide, flat area of land either side of the river in its lower course. It is covered with water during times of flood.

What causes a Floodplain?

Lateral erosion and the formation/migration of meanders have caused the floodplain to get wider, interlocking spurs have been eroded away. When a river floods onto the floodplain the water becomes shallow and the river's velocity decreases leading to deposition.

What are Levees?

Levees are natural embankments along the edges of a river channel.

What causes Levees?

They are formed when the river deposits material as it floods. During a flood the river will deposit its heaviest material first (i.e. closest to the banks). Over the years, material builds up to create a levee. The floodplain also gets built up with the fine sediment to create alluvium which makes the floodplain very fertile.

Where is Dorset located?

Dorset is located on the southern coast of the UK. It is called the Jurassic Coast as it has lots of fossils dating back to the Jurassic period.

How have Geomorphic Processes created Swanage Bay?

The cliffs backing Swanage Bay are made of clay, which is a soft rock. Towards the northern end of the bay the cliffs are covered in vegetation, stabilising them and protecting them from erosion. Elsewhere, the cliffs are not covered by vegetation, so wet weather weakens them causing slumps. Longshore drift affects the bay carrying material (mainly gravel) from the south to the north of the beach. Erosion is the dominant process in the bay with the beach losing material year on year.

How have Geomorphic Processes created The Foreland, Old Harry and his Wife?

In between the two bays (Studland and Swanage Bays) is a headland named the Foreland. This is made of chalk which is a harder rock. An arch at the end of the headland has collapsed to form a stack called Old Harry and a stump called Old Harry's Wife. Chemical weathering and erosion are gradually wearing down these down. Biological weathering caused by the vegetation on the top of the headland is also breaking up the rock.

How have Geomorphic Processes created Durdle Door?

This is an arch which has formed on a hard limestone headland. It is unusual as it has formed parallel to the coastline. Erosion by waves opened up a crack in the headland, which then became a cave and eventually an arch. The arch is gradually being worn away by mechanical, chemical and biological weathering.

How have Geomorphic Processes created Lulworth Cove?

This is an arch which has formed on a hard limestone headland. It is unusual as it has formed parallel to the coastline. Erosion by waves opened up a crack in the headland, which then became a cave and eventually an arch. The arch is gradually being worn away by mechanical, chemical and biological weathering.

How have Geomorphic Processes created Chesil Beach?

This is a tombolo (spit which connects mainland to an island). It connects the Isle of Portland to the mainland. It has been created by longshore drift. Behind Chesil Beach is a lagoon called The Fleet Lagoon.

How does Temperature influence Geomorphic Processes on the Dorset Coast?

• The Dorset Coast has warm, dry summers (around 21C in July) and mild and wet winters (average minimum temperature in January is about 3C)

• Salt weathering is the dominant form of mechanical weathering, particularly in summer. The warm temperature cause sea water to evaporate from rocks quickly, leaving a build-up of salt crystals in tiny cracks in the rock.

• The mild winters mean that freeze-thaw weathering is less common because it's usually not cold enough for ice to form.

How does Wind influence Geomorphic Processes on the Dorset Coast?

• The Dorset Coast's location means that it's exposed to prevailing winds from the south-west.

• These prevailing winds can bring storms to the UK from the Atlantic Ocean. Storms bring high energy, destructive waves which increase erosion of the cliffs.

• Hydraulic action and abrasion both increase during a storm and erode the base of the cliffs. This makes the cliffs unstable, making mass movement more likely to happen.

How does Rainfall influence Geomorphic Processes on the Dorset Coast?

• The Dorset Coast receives relatively low amounts of rainfall annually, but can experience very wet winters, with rainfall heaviest during storm periods.

• Soils and rocks become heavier when they're saturated, which can make them more prone to mass movement.

• In January 2016, intense rainfall combined with high-energy waves during Storm Frank to cause the collapsing of cliffs between Burton Bradstock and West Bay.

How does Geology influence Geomorphic Processes on the Dorset Coast?

• The coastline is made from bands of hack and soft rock. These rocks have been eroded at different rates, which has created the area's coastal landforms, e.g. at Lulworth Cove.

• Soft rock like sandstone and clay are easily eroded by hydraulic action and abrasion.