The UKs Evolving Physical Landscape Flashcards
Define igneous rock
The earth’s oldest rocks formed by lava cooling, they are hard and fairly resistant to erosion
Two examples of igneous rock
Basalt, granite
Define sedimentary rock
Formed by sediments deposited by rivers and the sea
Two examples of sedimentary rock
Limestone, sandstone
Define metamorphic rock
Sedimentary rocks that are heated and compressed over millions of years
Example of metamorphic rock
Limestone becomes marble
Outline the relationship between relief and geology in the UK
More metamorphic and igneous rocks in areas of higher land, more sedimentary rocks in areas of lower land
Why are there more metamorphic and igneous rocks in areas of higher land?
Higher land is composed of mountains which must be made up of rocks which are fairly resistant to erosion
How has the UK’s geology changed over time?
250 million years ago the UK was covered in tropical seas which were home to tropical fish and coral which die and fall to the bottom of the sea to be found as tough sedimentary rocks
How have tectonics affected the UKs landscape?
300 million years ago the plate the uk sits on began to move northwards and convection currents began to move rocks from below the sea becoming land known as the Pennines, magma rising up could not break all the way through the crust which formed features like the Batholiths
How has glaciation affected the UK’s landscape?
Over 100,000 years ago the top half of the UK was covered in ice, heavy glaciers moved down the lake districts valleys very slowly eroding either side of the valley making it deeper and wider creating u-shaped valley with high walls and flat bottom, land in the uplands is eroded and clay, silt and sands were deposited into the lowlands
Define physical weathering
Caused by physical changes such as temperature change, freezing and thawing
Define biological weathering
Animals can wear away rocks, tree roots push open cracks in rocks
Define chemical weathering
Rainwater is acidic because it contains carbon dioxide, this reacts with the rock
Why is the valley bottom futile?
Rivers flow in the valley bottom instead of glaciers which deposit silt and mud known as alluvium
Explain freeze-thaw
Rainwater gets into cracks in rocks, freezes and expands which leads to the rock breaking in places so angular rock pieces collect on the ground
Why are landslides common in the Lake District (Uplands)?
Rain adds to the weathered rock so it slides easily
Define soil creep
The slow downward progression of rock and soil down a low grade slope
How did dry valleys form in the Weald (Lowlands)?
During and after the last ice age water in the chalk froze which made it impermeable however as the climate warmed, water seeped through the chalk
Define dip slope
Gentle slopes which follow the angle at which rocks were tilted
Summarise the shape of the Lake District’s landscape (3 things)
Deep u-shaped valleys filled by lakes, scree fragments making the ground rough, rivers depositing silt and mud to create a fertile valley bottom
Summarise the shape of the Weald’s landscape (5 things)
Undulating hills, alternate strata of more and less resistant rock forming scarp and vale topography,resistant rock forms escarpments, dip slopes, softer clays form vales
What do they use as field boundaries in the Yorkshire Dales (uplands) and in East Anglia (lowlands)?
Dry stone walls in Yorkshire dales and hedges in east anglia
What building materials do they use in the Yorkshire Dales and in East Anglia?
Boulders and rocks left by rivers along with limestone on the valley sides in YD, flint (a crystalline form of quartz) in EA
How fertile is the land in the Yorkshire Dales and East Anglia?
Less fertile soil in YD, fertile land for farming in EA
How is the land suited for sheep grazing in the Yorkshire Dales?
Sometimes in field and sometimes in upland fells, longhouses and farms built
Why are the uplands wetter than the lowlands?
Due to relief rainfall and mountains force air to rise and thus cool and create clouds
Why are lowlands warmer than uplands?
Temperatures decline with altitude because as air rises it expands and so it cools
Why is there more snow in the uplands than in the lowlands?
Lower temperatures cause precipitation to fall as snow and not rain sometimes
Why does rainfall increase with latitude?
As air rises it cools which leads to condensation and cloud formation which causes rainfall
Why is mass movement slower in lowland areas?
Land is not as steep as upland areas
What is the climate like in upland areas?
Colder and wetter than lowland
Describe clay
Sedimentary rock which is weak and impermeable so water cannot move through it so landscapes of this rock tend to be wide, flat plains with lots of lakes, streams and rivers. Found all over Britain
Describe chalk
Sedimentary rock which is strong and permeable so water can flow through it, forms cliffs when it occurs at coastlines but is only found in Lowland Britain. Water flowing through chalk flows out as springs along the line where permeable chalk meets impermeable clay
Describe granite
Igneous rock which is hard and susceptible to chemical weathering, impermeable and so its landscapes are badly drained (boggy)
What are tors?
Features of granite landscapes which are towers chemically weathered into blocks
How is slate formed?
This is a metamorphic rock formed when layers in original clay form weak planes in the slate
What are schists?
Rocks formed from clay which split easily
Describe carboniferous limestone
Sedimentary rock which is permeable and chemically weathered by rainwater. Limestone landscapes have distinctive features like underground caves
Why are there lots of streams in the Lake District?
High precipitation means there is a lot of surface run off over the impermeable rocks
How can floodplains form in lowland areas?
Rivers meander to erode a wide valley between two hills then deposit silt which has been eroded from the river channel. When there is prolonged and heavy rain rivers flood and water spreads out all over valley floor depositing silt to form a wide, flat floodplain
Identify 3 human activities which have formed distinctive landscapes in the UK
Agriculture, settlement, forestry
How has agriculture caused distinctive landscapes to form in the UK? 3 WAYS
Drainage ditches are built to drain away water from low lying agricultural land to allow crops to grow, trees cleared away to make room, straight lines on maps are not often produced by natural physical processes so are an indication of human activity
What is forestry?
Managing and caring for forests for different purposes such as nature conservation, landscaping, recreation and timber production
How has forestry caused distinctive landscapes to form in the UK? 2 WAYS
Many UK landscapes have been planted with trees (increased interception) sometimes in straight rows to make forestry processes easier to manage, UK would naturally be covered in deciduous woodland however some areas have been planted with conifers for timber production which are very distinctive
How has settlement caused distinctive landscapes to form in the UK? 5 ways
Settlements grew up where the landscape offered advantages such as good defensive locations (river meander loops), natural harbours good for fishing villages, shallow points of rivers used as fords, springs gave people reliable fresh water, in big cities some rivers and streams run in tunnels underground
