Edexcel GCSE Geography A - Topic 1A and 1B

ROCKS

Naturally occurring solid aggregates of minerals.

MINERAL

Naturally occurring inorganic crystalline substance with specific chemical composition.

PERMEABLE

Rocks that allow water to flow through them.

IMPERMEABLE

Rocks that do not allow water to flow through them.

POROUS

Rocks that contain many air spaces (pores).

JOINTS

Cracks in rocks formed without displacement.

FAULTS

Cracks in rocks formed with displacement, usually due to tectonic forces.

IGNEOUS ROCKS

Rocks formed by cooling & solidification of lava/magma.

EXTRUSIVE igneous rocks

Igneous rocks that form from rapidly cooled lava erupted from volcanoes onto the surface.

BASALT

An example of extrusive igneous rock with small crystals.

INTRUSIVE igneous rocks

Igneous rocks that form from slowly cooled magma solidifying within the crust.

GRANITE

An example of intrusive igneous rock with large crystals.

SEDIMENTARY ROCKS

Rocks formed by deposition of fragments previously eroded & transported.

BEDS

Layers in which sedimentary rocks are deposited.

SANDSTONE

A type of sedimentary rock formed from deposited sands.

CHALK

A sedimentary rock formed from the skeletons of marine creatures.

coal

A sedimentary rock formed from dead plants.

COMPACTED

The process by which deposited sediment turns into rock due to the weight of material on top.

CEMENTATION

The process that glues particles together in sedimentary rocks.

METAMORPHIC ROCKS

Rocks formed when igneous or sedimentary rocks are changed by heat or pressure.

CLEAVAGE JOINTS

Cracks between layers in metamorphic rocks.

SLATE

A metamorphic rock that mudstone metamorphoses into.

SCHIST

A metamorphic rock that forms from mudstone under extreme pressure & heat.

UPLAND LANDSCAPES

Areas of high land (over 300m) often with steep slopes.

LOWLAND LANDSCAPES

Areas of low land (under 300m) usually flat or gently undulating.

GEOLOGY of UK

Divides into 2 halves along a line from the mouth of River Tees to the mouth of River Exe.

TECTONICS

Processes that formed igneous & metamorphic rocks in the North & West.

Columnar jointing

Distinctive geological feature produced by the quick cooling of basalts under water, exemplified by the Giant's Causeway.

Stickle Tarn

A lake formed in a bowl-shaped depression called a corrie, created by glacial erosion.

Glacial erosion

Process where ice slips forward, scouring the base of landforms by abrasion.

Freeze-thaw weathering

Weathering process where water fills cracks in rock, expands by 10% when freezing, and widens cracks.

Scree slope

Accumulation of angular fragments below a tarn, formed by blockfall slope processes.

Post-glacial river

River that eroded the steep-sided v-shaped valley called Stickle Ghyll from Stickle Tarn.

U-shaped valley

Wide, steep-sided valley formed by glacial deposition of boulder clay, exemplified by Langdale.

Permafrost

Underlying chalk bedrock in South Downs that was frozen year-round during the Devensian Glacial.

Solifluction

Slope process where surface layers thaw, become saturated, and slump downhill.

Carbonation

Chemical weathering process that continues to dissolve chalk, producing rounded slopes with thin soils.

Forestry

Management of woodland for timber, with afforestation schemes increasing Scotland's woodland cover to 20% by 2015.

Deciduous woodland

Type of woodland that originally covered most of the UK, characterized by trees that shed leaves seasonally.

Coniferous woodland

Type of woodland found in northern Scotland, composed of trees that remain evergreen.

Agriculture

Practice of farming that includes grazing of sheep in uplands, resulting in moorland landscapes.

Dry stone walls

Walls created using local stone to separate farmlands in upland areas.

Hedgerows

Natural boundaries in lowland landscapes that separate irregular green fields, often removed for large-scale arable farming.

SETTLEMENT

In upland landscapes hamlets, villages & small towns dispersed across landscape.

Urban Sprawl

Many cities expanded dramatically since Second World War.

COAST

Where land meets sea.

WEATHERING

Break down of rock in situ (in place), usually by atmospheric processes.

EROSION

Break down of rock & its immediate removal by same agent (e.g. wave, river, glacier, wind).

MASS MOVEMENT

Down slope transfer of material under force of gravity.

MECHANICAL WEATHERING

Breakdown of rock in situ into smaller pieces of same material, e.g. freeze-thaw weathering.

CHEMICAL WEATHERING

Breakdown of rock in situ into smaller particles, some of which of different chemical composition to original rock minerals.

BIOLOGICAL WEATHERING

Breakdown of rock in situ by living organisms or organic matter.

PLANT ROOT WEATHERING

Seeds falling into cracks in rock germinate in moist conditions. As plant grows, roots expand & exert outward pressure on rock until fractures.

ORGANIC ACID WEATHERING

Organic acids from faeces/ urine of animals or birds, or from decaying dead animals, react with rock minerals breaking bonds between particles.

SLIDING

Downslope movement of material along near straight shear plane.

SLUMPING

Downslope rotational movement of material along curved shear plane.

WAVES

Erode rock at coast.

ABRASION

Occurs when waves throw carried load items, e.g. pebbles, against cliff & impact breaks off pieces of rock.

HYDRAULIC ACTION

Occurs when force & weight of water itself impact against cliff & break off pieces of rock.

SOLUTION

Occurs when sea water dissolves rock minerals, e.g. calcium carbonate in limestone.

ATTRITION

Occurs when load items carried by wave are themselves broken down through impact with each other or with cliff.

TRACTION

Rolls heavy load items, e.g. cobbles, pebbles, along sea bed.

SALTATION

Bounces light load items along bed, e.g. small pebbles, sand grains.

SUSPENSION

Carries very light particles aloft in water, e.g. clays.

LONGSHORE DRIFT

Occurs when wave approaches beach at angle. Swash carries particle up beach at angle.

DEPOSITION

Occurs when transport of load items ceases.

Energy loss in deposition

Deposition takes place when waves no longer have sufficient energy to continue to transport material.

Causes of energy loss

Energy lost through friction, reduction in wind energy, or dispersal of energy by wave refraction.

ROCK TYPE

Affects what coastal LANDFORMS are present.

HARD ROCK

Has strong cohesive bonds & resists weathering, erosion & mass movement.

CLIFFS

Hard rock tends to form tall, steep CLIFFS & projecting HEADLANDS.

SOFT ROCK

Has weak cohesive bonds & is easily weathered, eroded & subject to mass movement.

BAYS

Soft rock may be eroded back to form BAYS.

GEOLOGICAL STRUCTURE

The characteristics & arrangement of different rock units.

CONCORDANT coasts

Have rock layers running parallel to coastline, producing straight coastline.

DISCORDANT coasts

Have rock layers at an angle to coastline, forming BAYS and HEADLANDS.

WAVE ENERGY

Determined by WIND STRENGTH and WAVE FETCH.

WAVE FETCH

Uninterrupted distance of open water over which wind can blow.

BREAKING WAVES

Occurs when wave approaches shore and topples forward.

SWASH

Water flows up beach as wave energy is exhausted.

BACKWASH

Gravity drags water back down beach after swash.

DESTRUCTIVE WAVES

High energy waves with large wave height, frequent with 11-15 per minute.

CONSTRUCTIVE WAVES

Low energy waves with low wave height, less frequent with 6-9 per minute.

UK TEMPERATE MARITIME CLIMATE

Characterized by warm, wet summers & mild, wet winters.

COASTAL RETREAT

Occurs when cliff collapse or beach erosion shifts land/sea boundary in landwards direction.

SEASONALITY of UK climate

Produces more intense WEATHERING in winter.

CARBONATION WEATHERING

Weathering process that is more prevalent in winter due to higher rainfall.

COASTAL EROSION

The process by which coastlines are eroded by natural forces such as waves and currents.

STORM FREQUENCY

The occurrence of storms, which is higher in winter than in summer.

STRONGER WINDS

Winds that are generated by storms, creating higher energy waves.

HIGHER ENERGY WAVES

Waves with increased force that lead to more rapid coastal erosion.

WAVE HEIGHT

The vertical distance between the crest and trough of a wave, which is larger during storms.

CLIFF collapse

The failure of a cliff face due to erosion processes, often accelerated during storms.

CAVES

Natural underground spaces formed by erosion processes in headlands.

ARCH

A natural opening formed when two caves on either side of a headland erode and connect.

STACK

A column of rock that remains after the arch has collapsed.

BEACH material

Sediment found on beaches that can be eroded by destructive waves.

SALT MARSH ecosystems

Coastal wetlands that can be eroded by wave action, particularly behind spits.

PREVAILING WINDS

Winds that dominate a region, affecting wave energy and coastal erosion.

HARD cohesive rock

Rock types that are resistant to erosion due to their strength and lack of weaknesses.