UK's Evolving Physical Landscape Flashcards
UKs geology
> There’s a distinct relation between UK landscape and its’ geology.
Rock type can have economic value (marble, coal).
Cornwall has large amounts of tin + copper making it wealthy.
Huge strata of coal helped to make Britain the world’s first industrial nation.
Other resources include building stone (marble) + raw materials (iron ore).
There are 3 types of rock.
Geology definition
> Rock type.
The 3 rock types
> Igneous.
Sedimentary.
Metamorphic.
Igneous Rock
> World’s oldest rock.
Formed from lava and magma when in cools deep underground.
Very resistant
E.g. granite, Giants Causeway in N. Ireland.
Sedimentary Rock
> Formed by layers of deposited materials.
E.g. chalk.
Very porous, medium resistance.
Chalk Cliffs in Southern England.
Metamorphic Rock
> Heated and compressed during igneous activity.
E.g slate and marble.
Found in 19th Century copper mines in west Cornwall.
Very resistant.
Ice Age Definition
> When massive amounts of ice spread over the Earth.
>The last one was around 10,000 years ago.
Impact of Glaciation on the UKs Landscape
> Most of Britain was covered in ice so most of our landscape is a result of ice erosion and deposition.
The last one:
-altered river valleys, making them deeper and widening them into U-shaped troughs.
As they melted, glaciers left features like Malham Cove with a spectacular waterfall.
Glacier Definition
> A slowly moving mass or river of ice formed by the accumulation and compaction of snow on mountains.
Erosion
> The process where rocks are worn away by the action of wind, water, ice or waves.
Weathering
> When weather, plants and animals breakdown rocks on the spot without moving them.
There are 3 types: biological, chemical and physical.
Freeze-Thaw Weathering
> In glacial environments, water in rocks freezes and expands, weakening the rocks.
When water freezes in the rocks it expands by 10% in volume.
Makes material more prone to erosion from glaciers.
Pieces of rock break away and become scree at base.
When scree’s trapped under glaciers, they significantly aid erosion.
Plucking
> Occurs when rocks and stones are frozen to the base/sides of a glacier and pluck ground and rock face as the glacier moves, leaving behind a jagged landscape.
Abrasion
> Scratching and scraping of river and banks by stones and sand in the river.
Movement of Glaciers
> They move slowly - 7-10km per year - great power.
Basal slip: sudden movement.
As glacier melts it’s lubricated allowing it to move.
Glaciers change shape as they are made from ice crystals - internal deformation.
Middle moves faster than the edges and it slows as it hits objects, meaning ice gets stretched and squashed so cracks called crevasses appear.
Glaciers erode rocks in 2 ways - plucking and abrasion.
As glaciers move they transport material that when deposited at the side, end or middle is called moraine.
