Topic 4 - UK's Physical Environment Flashcards
How does limestone form?
Limestone rocks in the north of England where formed in the carboniferous periods when the seas where warmer. When coral and fish died there skeletons fell to the sea floor, weight from above crushed these into rock. Calcium carbonate from rocks cemented them together, sand was then laid down on top of these rocks. These layers are known as strata.
How does the limestone get above the sea bed?
Tectonic processes pushed the limestone above from the sea bed.
How have tectonic processes shaped the UK landscape?
500 million years ago the UK was where Antarctica is now, it has slowly moved to its current position through tectonic processes. Furthermore, the UK was in separate parts and they slowly moved together. Between these collisions huge volcanoes occurred, erupting massive amounts of lava and creating mountains. Convection currents have also caused uplift of some land, shoving it upwards and further out of the sea
How has glaciation shaped the UK landscape?
12,000 years ago the uk had just come out of an ice age. during the ice age massive glaciers plucked rocks and altered the landscape. They left features such as u-shaped valleys, troughs, corries and eretes
What is igneous rock?
Magma cools and hardens. Rocks form crystals as it cools down. Igneous rocks are usually hard e.g granite
What is Sedimentary rock?
Layers of sediment are compacted together until they become solid rock e.g limestone and chalk are formed from tiny shells and skeletons of sea creatures. Limestone is hard, chalk is softer.
What is Metamorphic rock?
Metamorphic rock is formed when other ricks are changed by heat and pressure. New rock becomes harder and more compact. e.g shale becomes slate and with further pressure and heat, slate becomes schist
What is Chalk?
Chalk is a purer, younger from of limestone. It is very porous and has a medium resistance
What is Limestone?
Limestone is formed from layers of strata made from living organisms inn the water. It is permeable. It is generally resistant.
What is Clay?
It is formed from muds deposited by rivers or at sea. It is soft and crumbly and when compacted it becomes shale. It is generally weak.
What is Granite?
It is formed from magma cooling deep underground. It contains crystals of quartz, feldspar and mica. It is very resistant
What is Schist?
It is formed from further metamorphosis of slate, where it is partly melted and solidified. It is very resistant.
What is Slate?
It is formed from heated muds or shale. It is very resistant
What is the tees-exe line?
The line that separates the main rock types in the uk.
Is rock more or less resistant in upland areas?
more resistant
Is rock more or less resistant in lowland areas?
less resistant
What is the relief like in upland areas?
steeper
What is the relief like in lowland areas?
flatter
What is an example of an upland area?
The Lake District
What is an example of a lowland area?
The Weald
What is the highest point in UK upland areas?
Scaffel Pike (978m)
What is the highest point in UK lowland areas?
Crowborough Beacon (225m)
What is the geology like in The Lake District?
Igneous basalt rock from surface eruptions at Borrowdale and igneous granite from eruptions below the surface at eskdale. These are both resistant. There is sedimentary rock present too, formed when the UK was under tropical seas (350-250 million years ago) such as mud and sandstone.
What are tectonic processes like in The Lake District?
Large volcanoes 450-300 million years ago erupted in the Lake District in areas such as Borrowdale, this caused mountains to form - these are the mountains we see today.
What are the effects of the ice age in The Lake District?
The last ice age ended 12,000 years ago. It left a glaciated landscape. This includes: corries, U-shaped valleys and hanging valleys
What is the shape of the landscape like in The Lake District and how did they form?
After the ice age a glaciated landscape was left. An example of a glaciated feature is a corrie, they are armchair shaped and have very steep sides with a deep lake at the bottom. Another example is a U-shaped valley that is formed as a glacier moves through a valley and erodes the landscape
What are weathering processes like in The Lake District?
freeze thaw weathering - water falls into cracks in the rocks. At night the water freezes and expands by 9%. This increases the pressure on the rock. At day the water melts. This process is repeated until the rock finally breaks.
What are slope processes like in The Lake District?
mass movement e.g. landslides - They are common in upland areas as there is a lot of rainfall. This saturates the rocks/soil and increases their weight. This increased weight causes landslides
What are post glacial river processes like in The Lake District?
Due to upland areas previously having glaciers, they have U-shaped valleys. In these U-shaped valleys there are misfit rivers. They are called misfit rivers as they did not erode the valley.
What is climatological like in The Lake District?
There is increased rainfall in upland areas as there are many mountains, these mountains cause relief rainfall. Furthermore, the temperature is lower as the altitude is higher.
What is the effect of ice age in The Weald?
During glacial periods the gaps in the chalk froze making it impermeable. When seasonable snow melted it couldn’t infiltrate the chalk and instead ran over the top and eroded the valleys. Now it is warmer the water runs through the chalk and cannot be seen. These are called dry valleys
What is the shape of the landscape in The Weald and how did they form?
After the ice age there was a glaciated landscape. Dry valleys are valleys with no visible streams (they flow underground in the permeable chalk). Flood plains are formed when heavy rain leads to flooding, the overflowing river deposits silt on the valley floor, this forms a floodplain.
What are the weathering processes in The Weald?
Biological weathering -Burrowing animals burrow into a crack in the rock, making it larger and cracking the rock. Also, plant roots can grow into the cracks, and push them open, making them wider and deeper. Chemical Weathering - Rainwater absorbs CO2 as a by product of pollution, rain becomes a weak carbonic acid, acid reacts with the calcium carbonate in limestone/chalk and dissolves the rock.
What are slope processes like in The Weald?
Soil creep - soils such as as sandstone and clay can absorb large amounts of moisture and become saturated, they can then move down the slope. Soil creep is the slowest of all mass movements
What are post glacial river processes like in The Weald?
The UK climate is very wet. Heavy rain can lead to flooding. When the rivers flood the overflowing water carries sediment and deposits silt on the valley floor forming a flood plain. The flood plain is very fertile
What are settlements like in upland areas?
Many farms and barns are isolated , not in villages. There are dispersed settlement patterns.
What are the building materials in upland areas?
Building material consists mostly of local slate, stone and wood as delivering from a distance would be difficult.
What are field boundaries like in upland areas?
Field boundaries are walls made of stone as they do not use cement. The boundaries work with the land and are not uniform
What is farming like in upland areas?
Animals such as sheep are farmed as they can survive in harsh conditions. They are less likely to farm crops.
What is Economic Activity like in upland areas?
They can sell products from their farm animals, this could consist of wool, meat and milk
What are settlements like in Lowland Areas?
more likely to have villages and shops rather than having isolated and dispersed settlements
What are the building materials in Lowland Areas?
They can use sand, clay and cement due to the lands geology. It is also much easier to import materials for building
What are field boundaries like in Lowland Areas?
The field boundaries are much more uniform and do not need to work with the land as the land is much flatter
What is farming like in Lowland Areas?
They are more likely to grow crops as the environment is much more habitable
What is Economic Activity like in Lowland Areas?
Both primary and tertiary sectors as in villages there are shops, schools and churches
How does seasonality impact coastal erosion?
Temperature in the UK varies with the seasons. Temperatures are coldest in the winter and hottest in the summer. Differences in temperature have an impact on processes. e.g. salt weathering
How does Storm frequency impact coastal erosion?
Storms are more frequent in the winter. The string winds cause high energy, destructive waves which increase erosion of the cliffs. Intense rainfall can cause cliffs to become saturated and therefore increase mass movement
How does Prevailing wind and fetch impact coastal erosion?
The prevailing winds in the UK are mostly warm south westerlies which bring storms from the Atlantic ocean. The UK’s south coast is exposed to these winds
What are sub aeriel processes?
Processes of weathering and mass movement
How does Rotational Slumping impact coastal erosion?
Rain falls and it accumulates at the boundary between sand and clay which lubricates the boundary. The sad is permeable and allows water to pass through. Clay is impermeable and prevents water moving through it. The sand becomes saturated and will dramatically slump diagonally.
How do rock slides impact coastal erosion?
Joints or bedding planes are aligned diagonally to the sea. Erosion at the base, or weathering at the top of the cliff causes the cliff to become unsupported. The rocks then slide in a straight diagonal line. (It is sometimes lubricated by rain)
What are the 3 different types of erosion?
Abrasion, Hydraulic Action and Attrition
What is abrasion?
Abrasion is when broken rock fragments and pebbles carried in the wave batter and scour the land; breaking off other pieces of rock and rubbing the surface
What is Hydraulic Action?
Hydraulic action is when a wave crashes against the land and compresses air and water trapped in the cracks in the rock. When the wave moves away teh air expands explosively and enlarges the cracks. Eventually it will break off the rock
What is attrition?
Attrition is when rock fragments grind and rub each other down into smaller and smaller fragments. Eventually rocks are smoothed into pebbles, then reduced to shingle, and finally end up as sand
What are the characteristics of destructive waves?
The waves that carry out erosional processes are called destructive waves. They are high, steep and have a high frequency (10-14 waves per minute). Their backwash is more powerful than their swash, this means that material is removed from the coast. Storms increase the erosional power of destructive waves which can lead to increased rates of coastal retreat.
What are the characteristics of constructive waves?
Deposition is when material being carried by the seawater is dropped on the coast, It occurs when water carrying sediment slows down so that it isnt moving fast enough to carry the sediment. Waves that deposit more material than they erode are called constructive waves. Constructive waves are low, long and have a low frequency (6-8 waves per minute). The swash is more powerful than the backwash and it carries the material up the coast. The backwash is weaker and does not take much material down the coast. Constructive waves deposit material such as sand and shingle along the coast to form beaches
How are destructive waves formed?
They are formed by strong winds that have blown over long fetches
How are constructive waves formed?
.They are formed by light winds that have blown over short fetches
What are more resistant rocks?
Resistant rocks such as igneous granite, and resistant sedimentary such as sandstone or limestone
What are less resistant rocks?
less resistant rocks such as clays or shales are more easily eroded
What are joints?
joints are small, usually vertical cracks found in many rocks. The more joints there are, the weaker the rock is
What are Faults?
Faults are larger cracks caused by past tectonic movement, where rocks have moved. The more faults there are, the weaker the rock is
What is a discordant coastline?
a discordant coastline is a coastline with alternating layers of rock perpendicular to the coastline
What is a concordant coastline?
a concordant coastline is alternating layers of rock parallel to the coastline
What is an example of a discordant coastline?
Bantry Bay
What is an example of a concordant coastline?
Lulworth cove
What features and landforms are found at discordant coastlines?
arches, stacks and stumps
What features and landforms are found at concordant coastlines?
coves but can also be featureless
How do headlands and bays form?
the sea attacks a section of coast with alternating bands of hard and soft rock. The bands of soft rock erode quicker than the bans of hard rock. This leaves a section of land jutting out into the sea called a headland. The areas where soft has eroded, next to the headland, are called bays.
How do arches, stacks and stumps form?
Waves are very strong where headlands jut out into the sea. These waves crash into the headlands and enlarge any cracks/faults in the rock through hydraulic action and abrasion. Repeated erosion and enlargement of these cracks causes a cave to form. Continued erosion deepens the cave until it breaks through the headland - forming an arch, e.g durdle door. Erosion and weathering continue to wear away the rock supporting the arch until it eventually collapses. This leaves behind a rock pillar called a stack. The base of the stack is weathered and eroded until the top falls off, leaving a stump.
How do wave cut notch’s and platforms form?
Weathering weakens the top of the cliff. Hydraulic action and abrasion caused by the sea erode the foot of the cliff. This forms a wave-cut notch. As erosion continues the notch is enlarged. The rock above the notch becomes unstable and eventually collapses. The collapsed material is carried back towards the sea by the backwash, this forms a wave cut platform. This process repeats and causes the cliff to retreat.
How does long shore drift work?
Waves follow the direction of the prevailing wind. This causes them to hit the coast at an oblique angle. The swash carries the material up the beach in the same direction as the waves. The backwash then carries material back down the beach at right angles, back towards the sea. Over time, material zigzags along the coast.
How is a spit formed?
A spit is formed at sharp bends in the coastline, e.g. At a river mouth. Longshore drift transports sand and shingle past the bend and deposits it in the sea. Strong winds and waves can curve the end of the spit, forming a recurved end. The sheltered area behind the spit is protected from the waves - lots of material accumulates in this area, which means plants can grow here. Over time, this sheltered area can become a mud flat or a salt marsh
How does a bar form?
A bar is formed when a spit joins 2 headlands together. The bar cuts off the bay between the headlands from sea. This means a lagoon can form behind the bar.
What is deposition?
Deposition is when material is deposited by constructive waves and forms landscapes such as: beaches, spits and bars
What is solution?
Parts of rock are dissolved by the weak acidity or salt in the water and are carried by the water
What is Suspension?
Suspension is when small particles are carried (suspended) in the water and carried along
What is Saltation?
Saltation is when slightly heavier particles are too heavy to be picked up by the sea but are light enough to bounce/hop along the sea bed
What is Traction?
Traction is when large pebbles that are too heavy to be picked up or bounced along, are rolled along the sea bed
What is a direct impact?
something caused by humans
What is an indirect impact?
something caused as a result of a direct impact
What is a direct impact of industry on the coastal landscape?
Easington Gas Works increases weight on the cliff which adds to rotational slumping mass movement. Pollution of the water, air and noise is a big problem and threatens wildlife in the surrounding area. These impacts are negative.
What is an indirect impact of industry on the coastal landscape?
Sand was dredged from the beach and under the sea to build up the height of the gas works. This has a consequence of increasing the height of the waves and making them more destructive. These impacts are negative
What is a direct impact of agriculture on the coastal landscape?
a decision has been made to not protect Tunstall farm as it is poor quality and low value. When the farmer ploughs the farm, it exposes the soil and rock. These impacts are negative