TOPIC 1 CHANGING LANDSCAPES OF THE UK INTRO Flashcards
What are the 3 types of rocks
Igneous
Metamorphic
Sedimentary
How are igneous rocks formed
Molten rock (magma) from mantle cools and hardens which forms crystals
Example of igneous rocks
Granite and basalt
How are sedimentary rocks formed
Layers of sediment are compacted together until they become solid rocks
Difference between sedimentary and igneous Rocks
Sedimentary are softer and so more easily eroded
Example of sedimentary rocks
Sandstone - made of sand sized particles which have been cemented together
Chalk - formed from tiny shells and skeletons of Dead Sea creatures
How are metamorphic rocks formed
Formed when other rocks eg sedimentary or igneous change by heat and pressure becoming harder and more compact
Example of metamorphic rock
Marble
3 causes of uk landscape being changed
Active volcanoes
Plate collision
Plate movements
Explain how active volcanoes change uk landscape
Volcanoes occur near plate boundaries
Volcanic eruptions forced magma through the Earth’s crust which cooled to form igneous rocks eg granite
Explain how plate collision change uk landscape
Collisions between tectonic plates cáuses rocks to be folded and uplifted forming mountain range. Many of these areas remain as uplands eg Scottish highlands - igneous rocks are hard and more resistant to erosion
Intense heat and pressure caused by plate collisions firmed hard metamorphic rocks in north Ireland
How does plate movement change the uk landscape
345-280 million years ago Britain was in the tropics and higher sea levels meant it was partly underwater - Carboniferous limestone formed in the warm shallow seas which can been seen in the uplands of Peak District
Youngest rocks in the uk were chalks and clays found in southern England which are softer so more easily eroded forming lowlandscapes
Characteristics of granite
Form igneous upland landscapes
Has lots of joints which aren’t evenly spread . Parts of the where there are more joints wear down faster vice versa ( fewer joint stick out to form tors)
Impermeable - does not water through creating moorland - large areas waterlogged land and acidic soil with low growing vegetation
Characteristics of basalt
Form igneous escarpments in uk uplands and cliffs at coast
Lava cools it can form columns. Cracks between columns may be eroded by glaciation and the sea to form steps eg giant causeway in Northern Ireland
Characteristics of slate and schist
Metamorphic rocks
Slate form in layers creating weak planes in the Rock. It is generally very hard and resistant to weathering but it is easily split into thin slabs.
Schists has bigger crystals than slate and also splits easily into small flakes
Slate and schist often form rugged, upland landscapes. They are impermeable which can lead to waterlogged and acidic soils
Characteristics of chalk
Chalk forms sedimentary hills in UK lowlands and at the coast. One side of the hill is usually steep and the other side is more gentle.
Chalk is permeable - water flows through it and emerges as a spring where it meets impermeable rock
Characteristics of sandstone
Sandstone is a sedimentary rock made from sand. Sandstone can be hard or soft.
Softer sandstones form lowland landscapes. Harder sandstones can form upland landscapes, e.g. the Torridon hills in Scotland.
Sandstone is porous - it has small gaps in it, so it can store water in underground aquifers.
How has the uk landscape been shaped by ice
glaciated landscapes are mostly found in upland areas in the north-west of the UK.
Ice is very powerful, so it was able to erode the landscape, carving out large U-shaped valleys in upland areas such as the Lake District.
Glaciation also affected lowland areas. Glaciers deposited lots of material as they melted. Landscapes formed by glacial meltwater and deposits extend south of where the ice sheets were.
E.g. large parts of eastern England are covered in till (an unsorted mixture of clay, sand and rocks) deposited by melting glaciers.
Physical process that alter the landscape
Weathering - breakdown of rock into smaller pieces. it can be mechanical, chemical or biological
Erosion - erosion wears away rock. During the last glacial period, ice eroded the landscape. Now river and seas erode the landscape . melting ice at the end of glacial periods made rivers much bigger than normal with more power to erode the landscape.
Slope processes - including mass movements, e.g. rockfalls, slides, slumps and soil creep.
Example where physical process are affected by climate
a cold climate increases the likelihood of freeze-thaw weathering
a wet climate increases the number of streams and rivers.
Physical process interact to create distinctive upland landscapes
large U-shaped valley was
eroded by ice - it has a flat floor and steep sides. The valley
contains a misfit river that is
too small to have created it.
Freeze-thaw weathering occurs on the steep back wall of the corrie.As the rocks are broken up there are rock falls, which form scree slopes.
There is lots of rain in Snowdonia and the rocks are mostly impermeable.
This means there are lots of streams that are eroding the steep sides of the corrie and forming gullies.
Physical process interact to create distinctive lowland landscapes
Dry valleys are found in UK lowland landscapes (valleys with no streams visible - they flow underground in the permeable chalk). They formed during glacial periods when the colder climate led to more freeze-thaw weathering and glacial snow melt meant that streams had much more water in them than they do today.
The UK has a wet climate - heavy rain can lead to flooding. The overflowing river deposits silt on the valley floor forming a flood plain.
How has humans changed the landscape through agriculture
Different landscapes have been adapted for different types of farming:
Arable - flat land with good soil, e.g. eastern England, is used for arable farming (growing crops).
* Dairy - warm and wet areas, e.g. south west England, are good for dairy farming. There are lots of large, grassy fields.
* Sheep - sheep farming takes place in the harsher conditions in the uplands. Sheep farming has led to a lack of trees on the hills (young trees are eaten or trampled before they get a chance to mature)
How has humans changed the landscape through forestry
1) Forestry is the management of areas of woodland - they can be used for timber, recreation or conservation.
2) The UK used to be covered in deciduous woodland, but there is very little natural woodland left.
3) Coniferous (evergreen) forests have been planted for timber. The trees are often planted in straight lines. When areas are felled, the landscape is left bare. This affects drainage and can lead to increased erosion.
4) In some places, deciduous woodland is being replanted to try to return the area to a more natural state.