Rocks, Resources and Scenery

Types of rock

Geological Time• Geological time is on a different

scale from human time. • Chalk was formed during the

Cretaceous period• Clay was formed during the

Mesozoic - Jurassic, Cretaceous and Tertiary periods

• Granite was formed about 280 million years ago in the Permian period of the Late Palaeozoic era.

• Carboniferous Limestone was formed 340 million years ago during the Carboniferous period of the Late Palaeozoic era

Simplified diagram

Rocks, Resources and Scenery

Rock Classification and CycleRocks belong to

one of three groups.

Igneous rocks e,g. granite. An intrusive igneous rock is formed by the cooling of magma deep underground.

Sedimentary rocks e.g. limestone, chalk and clay. Limestone (an organic rock) is precipitated from solutions and is formed by the accumulation of calcium carbonate in warm tropical seas. Clay (an inorganic rock) is formed by the compaction & cementation of sediments under the sea.

Metamorphic rocks are formed by heat underground. They change from one type of rock into another.

Granite in the Southwest

Limestone in Yorkshire

Chalk and clay in the south east

The rock cycle shows that all rocks are weathered and eroded and are washed into the sea where they form new rocks

Rocks, Resources and Scenery

WeatheringRocks are susceptible to

weathering. The type of weathering that is most effective is determined by the composition of the rock and the climate.

Mechanical weathering – freeze thaw weathering and exfoliation.

Chemical weathering – solution and carbonation.

Biological weathering.

Exfoliation – the outer layers of the rock break off

Freeze-thaw weathering

Carbonation: Rock is dissolvedCalcium carbonate (CaCo3) is dissolved carbon dioxide in rainwater or moisture in  surrounding air forms carbonic acid and reacts with the minerals in the rock. The process weakens the rock thus breaking it down in the process. e.g.: Calcium Carbonate + Water + Carbon Dioxide ---> Calcium Carbonate (soluble)

Biological weathering – the roots from plants and trees break up the rock.

Rocks, Resources and Scenery

Different rocks create contrasting landforms and landscapes - granite

Rocks, Resources and Scenery

Tors

Tors are hilly outcrops of granite. They are formed when the overlying rocks are eroded leaving a mound of solid granite which is deeply jointed. Dartmoor is known for its tors e.g. Yes Tor, 619 m and Haytor 457 m.

Moorland

Moorland is the landscape formed on granite. It consists of poorly drained land as the granite is impermeable and so bogs and marshes (mires) form. There are few trees and peat covers large areas. The land is suitable for pastoral farming and tourism.

Different rocks create contrasting landforms and landscapes – chalk

and clay

Rocks, Resources and Scenery

Dip slope

Scarp slope

Escarpment/cuesta

Spring line

Spring line settlement

Clay valechalk

Dry valley

Escarpment/cuesta – a range of chalk hills with a steep scarp slope one side and a gentle dip slope the other side.

Clay vale – an area of lowland.

Dry valleys are valleys without water. They were formed during a wetter periods.

Spring lines are found where the chalk changes to clay or where the water table reached the surface. A series of springs are found in a line along the base of the escarpment.

Different rocks create contrasting landforms and landscapes – limestone

Rocks, Resources and Scenery

Surface features:Limestone pavements – areas of bare limestone which has been weathered. The joints are called grykes and the slabs clints.Swallow holes – deep holes in the limestone down which rivers disappear.Dry valleys – valleys where the river has disppeared.Caverns – large underground caves formed by the solution of the liemstone by the underground rivers.Resurgences – springs where the underground river reappears at the surface.

Underground features:Stalactite – a column which hangs down from the ceiling.Stalagmite – a column that grows up from the floor.Pillar – a column formed where a stalactite meets a stalagmite.Curtain – a very wide column of limestone.

Limestone pavement –clints (slabs) and grykes (joints)

Swallow hole

Resources, land and sceneryRocks, Resources and Scenery

Granite, chalk and clay and Carboniferous limestone provide resources to extract, land to farm on and unique scenery for tourism.

Building stone: Granite can be used for kitchen work surfaces, floor tiles and grave stones. Limestone can be used for dry-stone walls, house building and garden stone for patios/rockeries.

Production of cement: Limestone and chalk are both quarried to make cement.

Opportunities and limitations for farming: In granite areas 90% of the land is farmed. Open moorland is used for pastoral farming (sheep,cattle and ponies)

Arable farming on fringes (hay and grass. Granite has

poor thin soils, poor drainage and very heavy rainfall which make farming difficult.In limestone areas sheep farming is found but the thin soils make arable farming difficult.Chalk is good for pastoral farming and some arable as short sprungy grass grows well. Clay is good for arable farming as it has deep fertile soils and also for dairy farming as grass grows well.

Chalk AquifersRocks, Resources and Scenery

Aquifers are stores of underground water. An aquifer is under the London basin. Rain falls on the chalk hills and percolates down through the rocks. It is stored in the chalk sandwiched between the clay layers. To reach the water, wells are sunk. Water supply in London depends on this groundwater.

Opportunities for tourism and costs and benefits of this

Rocks, Resources and Scenery

Limestone: Yorkshire Dales National Park•Spectacular landscape•Steep valleys•Cliffs•Extensive grassy plateauxGranite: Dartmoor National Park•Wild open moorland•Abundant wildlife•Area of outstanding beauty•Many types of outdoor activity•Accessibility (near to motorways and urban areas)•Literature (Charles Dickens, Arthur Conan Doyle)

Costs (problems) Benefits (good things)

•Traffic jams•Litter•Farm gates left open•Animals worried by dogs•High shop prices•High house prices due to demand for holiday homes

•Visitors spend money in shops, cafes and hotels•Jobs for locals are created in restaurants, hotels•Local craft shops and farms gain extra income

QuarryingRocks, Resources and Scenery

Demand for resources has led to quarrying. This is an important issue and has led to conflict and debate.

Quarrying is digging out of rocks and minerals from the earth’s surfaceLimestone and slate are the rocks usually quarried.Quarrying can include sand and gravel extraction and open cast mining.

Case Study: Hope Quarry, Castleton, Yorkshire Dales. One of the largest quarries in the Peak District. It supplies 2 million tonnes a year to Hope Cement works.Hope Cement works produces 1.3 million tonnes of cement every year.Creates jobs - 182 local people employed and it increases the local economy.

Economic Social Environmental

Brings jobs into rural community

Higher tax revenue used to build new schools and roads.

People have jobs and feel more prosperous.

When quarry finishes, can build new resource e.g. shopping centre or ecocentre.

When quarry closes people lose their jobs.

Dust, Noise, Blot on landscape, Large big hole left, Wildlife habitats destroyed, Ground water polluted

Advantages

Disadvantages

Impact of quarryingRocks, Resources and Scenery

Impact of quarrying on the environment can be reduced by careful, sustainable management.

There are ways of reducing the impacts. At Hope Quarry they plant trees and use landscaping. They aim to reduce dust by using trains to take stone away rather than lorries. They reduce CO2 by planting more trees.

After quarrying has finished: There are strict environmental controls and quarry owners are now expected to restore landscape to a better state than before. They can replace topsoil and use for farming. For recreation: they can make tracks for mountain biking & can use waste tips for dry ski slopes. They can create wildlife areas by planting trees and scrubs and creating ponds and set up wetland nature reserve in old pits. They can be used for retailing e.g. Bluewater and science e.g. Eden Project.