LC Geography key terms

The zone where two tectonic plates meet. It may be divergent (plates separating), convergent (plates colliding) or transform (plates sliding past each other), and most earthquakes and volcanic activity occur along these zones.

A convergent boundary where one denser oceanic plate sinks beneath another plate into the mantle. The sinking plate melts, producing magma that feeds volcanoes, and the sudden release of built-up stress causes powerful earthquakes.

A long underwater mountain chain formed where two plates pull apart and magma rises to create new oceanic crust. The newest rock lies at the ridge crest and the crust becomes older with distance from it.

The process by which new oceanic crust is created at mid-ocean ridges as magma rises and solidifies, then moves away from the ridge on both sides. Magnetic striping and age patterns in ocean-floor rock provide evidence for it.

A mountain range formed when layers of sedimentary rock are compressed and buckled upwards at a convergent plate boundary. The Alps and the Himalayas are classic examples produced by continental collision.

The breakdown of rock in situ by physical, chemical or biological processes, without the material being carried away. Freeze-thaw action and carbonation are common examples in Irish limestone landscapes.

The downslope transfer of soil and rock under the influence of gravity, ranging from slow creep to rapid landslides and mudflows. It is often triggered when heavy rain or human activity reduces slope stability.

The wearing away of a river bed and banks by hydraulic action, abrasion, attrition and solution. Erosion, combined with transport and deposition, shapes landforms such as waterfalls, meanders and floodplains.

A bend in a river channel formed by faster flow eroding the outer bank and slower flow depositing material on the inner bank. Continued erosion and deposition cause meanders to migrate downstream over time.

The flat area of land beside a river that is built up by sediment deposited during floods. It provides valuable farmland but carries flood risk when rivers overflow or when building covers permeable surfaces.

A landscape formed on soluble rock such as limestone, where chemical weathering creates features including caves, swallow holes, clints and grikes. Underground drainage is typical because surface water sinks rapidly through joints.

A graph showing river discharge or water level against time after a rainfall event. Its lag time and peak height reveal how quickly water reaches the channel and how the catchment responds to precipitation.

The area of land drained by a river and its tributaries, bounded by a watershed. Inputs of precipitation are balanced against outputs such as evaporation and river discharge within this catchment system.

A body of permeable rock or sediment that can store and transmit groundwater in usable quantities. Wells and springs draw on aquifers, so over-abstraction or pollution can seriously reduce water supply.

A large-scale ecological region defined by its climate and dominant vegetation, such as tropical rainforest, savanna or tundra. Each biome supports characteristic soils, plants and animal communities adapted to its conditions.

A vertical section through soil showing distinct horizons from surface litter down to weathered bedrock. Horizon thickness, colour and texture reflect climate, vegetation, drainage and the length of soil development.

The removal of dissolved nutrients and minerals from upper soil horizons as water percolates downwards. It is pronounced in wet climates and can leave soils acidic and infertile for farming.

The degradation of dryland ecosystems into desert-like conditions through drought, overgrazing, deforestation and poor irrigation. It reduces the land's capacity to support crops and pasture, threatening livelihoods.

A region defined by shared physical characteristics such as relief, geology or drainage, for example an upland or lowland area. Its boundaries follow natural features rather than administrative lines.

A region defined by the area served by a particular activity or system, such as a city's commuter catchment or a river basin authority. Its boundary is drawn where interaction with the centre becomes weak.

A relatively wealthy, economically dynamic area that attracts investment, jobs and migrants, often containing the main cities and infrastructure. It contrasts with the less developed periphery, which may supply labour and resources.

A region lying at the edge of economic activity, typically with lower incomes, weaker infrastructure and out-migration. Development policy often targets peripheries to reduce regional imbalance with the core.

Uneven development between regions of a country, shown by differences in income, employment, population change and services. It may arise from geography, historical investment patterns or unequal access to transport and education.

Work that directly extracts or harvests natural resources, such as farming, fishing, forestry, mining and quarrying. It usually dominates early stages of economic development and employs fewer people as economies industrialise.

Work that processes raw materials into manufactured goods, including food processing, textiles, chemicals and electronics assembly. It adds value to primary products and may be located to reduce transport costs or access labour.

Work that provides services rather than goods, such as retail, transport, tourism, finance, education and healthcare. It now accounts for most employment in high-income economies.

Highly specialised knowledge-based work involving research, design, software development and consultancy. Such activity clusters in cities and science parks where skilled graduates and good communications are available.

The factors that determine where a factory or firm is placed, including raw materials, energy, transport, labour, markets and government incentives. Different industries weight these factors differently, which explains varied spatial patterns.

A firm whose location is not strongly tied to raw materials or markets because its product is light and easily transported. Such firms often locate near skilled labour, transport links or pleasant surroundings.

A large company that operates production or service facilities in more than one country, often coordinating them from a headquarters in a home country. It can shift investment between places in search of lower costs or new markets.

Investment by a firm in productive assets or operations in another country, such as building a factory or acquiring a local company. Governments attract it with incentives because it can create jobs and transfer technology.

The growing interconnection of economies and societies through trade, investment, migration and information flows. It links distant producers and consumers but can also increase vulnerability to distant shocks.

A model showing how birth and death rates change through stages as a society develops, from high stationary rates to low stationary rates. It helps explain population growth patterns and differences between countries.

A bar chart showing the age and sex structure of a population. Its shape reveals past events such as wars or baby booms and indicates future demand for schools, housing and healthcare.

The proportion of a population that is not in the labour force, such as children and older people, compared with those of working age. A high ratio places pressure on workers to support dependants.

The movement of people from the countryside to towns and cities, usually driven by push factors such as low farm incomes and pull factors such as jobs and services. It can cause rapid urban growth and housing shortages.

The rising share of a population living in towns and cities, together with the physical growth of urban areas. It is driven by natural increase and rural-urban migration and requires investment in housing and services.

Conditions that respectively encourage people to leave a place or attract them to another. Push factors include unemployment and conflict; pull factors include higher wages, education and family connections.

Development that meets present needs without compromising the ability of future generations to meet theirs. It balances economic growth, social wellbeing and environmental protection in planning and resource use.