GCSE Geography: Rock types Rock Type Formation Characteristics Landscape Case study Granite: intrusive igneous 280 million years ago in subduction zones (meeting of continental shelves) where batholiths/plutons (giant masses of magma) cool underground. - Hard & durable - Criss cross joints - Contains quartz, black mica and pink feldspar - Impermeable - Decays via hydrolysis Found in Cairngorms, Lake District, Devon, Cornwall and the Scilly Isles. - Marshy , wet climate - Acidic soil - Tors (exposed outcrops) Dartmoor - Ten tors - Livestock farming - Military training - Meldon resevoir - Granite & china clay quarries Carboniferous limestone: sedimentary 340 million years ago in warm, tropical seas where calcium carbonate (CaCO3)from dead crustaceans accumulated on the seabed. - Physically strong but chemically weak - Carbonation - Fossils - Horizontal bedding planes - Blocky appearance - Permeable but non-porous (water passes through joints) Found in Penine Hills and the Mendips, distributed in bands. - Karst scenery - Gorges and dry valleys - Asymmetric valleys - Limestone pavement (clints and grykes) - Caverns and caves - Stalactites, stalagmites, pillars and curtains - Swallow/sink holes - Resurgent streams - Alkaline soil (good pasture) Cheddar Gorge - 500,000 tourists p.a - 350 graded rock climbing passages. - Whatley Quarry & other quarries employ 2000 and £150 mill. profits p.a - Stone used in Bath and Bristol and roads in SW - Pastoral farming in Mendips on calcareous grassland. - Cheddar Yeo river feeds Cheddar reservoir, holding 135 million gallons. - Mendip forestry ltd (ash trees) Chalk: sedimentary Cretaceous period (145-65 million years ago) in shallow, tropical seas where crustaceans rich in calcium carbonate accumulated in beds. A purer form of limestone. - Permeable - White - Heavily jointed and porous - Physically weak - Chemically vulnerable - Contains deposits of Gypsum and Flint Clay is very common. It exists alongside chalk in the North and South Downs around Sussex, the Chilterns and the Yorkshire Wolds. - Chalk aquifers - Clay vales - Springs - Dry valleys (from ice age) - Synclines and antilines - Escarpments (with scarp & dip slopes) - Rendzina soil Sussex Downs - Naturally filtered water used for watercress and paper production. - Horse racing (Epsom) - Water pumped from chalk aquifers to service London. - Cretaceous meadowland hosts rare wildlife such as the Bee Orchid and the Adonis Blue butterfly. - Lack of vegetation and gentle slopes allow paragliding and hang gliding. - The Icknield Way (E. Thomas) Clay: sedimentary Mainly Jurassic and Cretaceous periods (199-65 million years ago) as a result of the chemical decomposition of other rocks like granite or the disintegration of shale. - Weak - Impermeable - Contains kaolinite. - Contains tiny pores that are easily water logged

AQA GCSE Geography - Rock Types

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Description of Chalk, Limestone, Clay and granite, their distribution in the UK and a case study.

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GCSE Geography: Rock types

Rock Type Formation Characteristics Landscape Case studyGranite:intrusive igneous

280 million years ago in subduction zones (meeting of continental shelves) where batholiths/plutons (giant masses of magma) cool underground.

- Hard & durable- Criss cross joints- Contains quartz, black mica

and pink feldspar- Impermeable- Decays via hydrolysis

Found in Cairngorms, Lake District, Devon, Cornwall and the Scilly Isles.- Marshy, wet climate- Acidic soil- Tors (exposed outcrops)

Dartmoor- Ten tors- Livestock farming- Military training- Meldon resevoir- Granite & china clay quarries

Carboniferous limestone:sedimentary

340 million years ago in warm, tropical seas where calcium carbonate (CaCO3)from dead crustaceans accumulated on the seabed.

- Physically strong but chemically weak

- Carbonation- Fossils- Horizontal bedding planes - Blocky appearance- Permeable but non-porous

(water passes through joints)

Found in Penine Hills and the Mendips, distributed in bands.- Karst scenery- Gorges and dry valleys- Asymmetric valleys- Limestone pavement (clints

and grykes)- Caverns and caves- Stalactites, stalagmites,

pillars and curtains- Swallow/sink holes- Resurgent streams- Alkaline soil (good pasture)

Cheddar Gorge- 500,000 tourists p.a- 350 graded rock climbing

passages.- Whatley Quarry & other

quarries employ 2000 and 150 mill. profits p.a

- Stone used in Bath and Bristol and roads in SW

- Pastoral farming in Mendips on calcareous grassland.

- Cheddar Yeo river feeds Cheddar reservoir, holding 135 million gallons.

- Mendip forestry ltd (ash trees)Chalk:sedimentary

Cretaceous period (145-65 million years ago) in shallow, tropical seas where crustaceans rich in calcium carbonate accumulated in beds. A purer form of limestone.

- Permeable- White- Heavily jointed and porous- Physically weak- Chemically vulnerable- Contains deposits of Gypsum

and Flint

Clay is very common. It exists alongside chalk in the North and South Downs around Sussex, the Chilterns and the Yorkshire Wolds.- Chalk aquifers- Clay vales- Springs- Dry valleys (from ice age)- Synclines and antilines- Escarpments (with scarp &

dip slopes)- Rendzina soil

Sussex Downs- Naturally filtered water used for

watercress and paper production.

- Horse racing (Epsom)- Water pumped from chalk

aquifers to service London.- Cretaceous meadowland hosts

rare wildlife such as the Bee Orchid and the Adonis Blue butterfly.

- Lack of vegetation and gentle slopes allow paragliding and hang gliding.

- The Icknield Way (E. Thomas)

Clay:sedimentary

Mainly Jurassic and Cretaceous periods (199-65 million years ago) as a result of the chemical decomposition of other rocks like granite or the disintegration of shale.

- Weak- Impermeable- Contains kaolinite.- Contains tiny pores that are

easily water logged