geography topic 4 coastal change and conflict

Geology

The type, structure and age of rocks that make up an area

Upland landscapes

High, steep areas made mainly from hard igneous and metamorphic rock

Lowland landscapes

Low, flat or gently rolling areas made mainly from softer sedimentary rock

Igneous rock

Rock formed from cooled magma or lava (e.g. granite)

Sedimentary rock

Rock formed from layers of sediment (e.g. chalk, limestone, clay)

Metamorphic rock

Rock changed by heat and pressure (e.g. slate, schist)

Glacial erosion

The wearing away of land by ice during the last Ice Age

Glacial deposition

Material dropped by melting glaciers, shaping upland landscapes

Weathering

The breakdown of rock in place by physical, chemical or biological processes

River processes

Erosion, transportation and deposition shaping post-glacial landscapes

Slope processes

Movement of material downhill due to gravity (e.g. landslides)

Human activity (landscape change)

Agriculture, forestry and settlement altering landscapes over time

Coastal erosion

The wearing away of the coastline by the sea

Hard rock

Resistant rock that erodes slowly, forming headlands

Soft rock

Less resistant rock that erodes quickly, forming bays

Discordant coastline

Coastline where bands of rock meet the sea at right angles

Concordant coastline

Coastline where bands of rock run parallel to the shore

Headland

Resistant rock sticking out into the sea

Bay

Area of softer rock eroded more quickly between headlands

Cave

A hollow formed by erosion along cracks in a cliff

Arch

A cave eroded through a headland

Stack

An isolated pillar of rock formed after an arch collapses

Cliff

A steep rock face formed by marine erosion

Wave-cut platform

Flat rocky surface left after cliff retreat

Destructive waves

Powerful waves that cause erosion

Mass movement

Downhill movement of rock and soil due to gravity

Longshore drift

The movement of sediment along the coast by angled waves

Constructive waves

Gentle waves that deposit sediment

Spit

A narrow ridge of sand or shingle extending from the coast

Bar

A ridge of sand that cuts off a bay, forming a lagoon

Beach

Area of deposited sand or shingle along the coast

Coastal development

Building on the coast, increasing erosion risk

Agriculture (coasts)

Farming practices that can increase erosion and runoff

Industry (coasts)

Ports and industry changing sediment movement

Coastal management

Strategies used to reduce erosion and flooding

Named coastal landscape

A specific coastline studied to show human and physical interaction

Significance of location

Why a coastline is important (economic, environmental, social)

Coastal flooding

When sea water covers normally dry land

Climate change (coasts)

Causes rising sea levels and more storms

Sea-level rise

Increase in average sea height due to melting ice and thermal expansion

Storm frequency

How often storms occur, increasing erosion risk

Hard engineering

Man-made structures to control erosion (e.g. sea walls)

Sea wall

A concrete barrier that reflects waves

Groynes

Wooden or rock barriers that trap sediment moved by longshore drift

Soft engineering

Natural, sustainable coastal management methods

Beach replenishment

Adding sand or shingle to beaches to reduce erosion

Slope stabilisation

Reducing mass movement using vegetation or drainage

Do nothing

Allowing natural processes to continue without intervention

Managed retreat (realignment)

Allowing some coastal areas to flood to reduce risk elsewhere

Integrated Coastal Zone Management (ICZM)

Long-term sustainable management of the coastline

Cost-benefit analysis

Comparing advantages and disadvantages of management options

Conflict at the coast

Disagreement between groups over how the coast should be managed

Formation of a headland and bay

On a discordant coastline, soft rock is eroded quickly by hydraulic action and abrasion to form bays, while hard rock resists erosion and is left protruding as headlands

Formation of a cliff

Destructive waves erode the base of the coast by hydraulic action and abrasion, creating a steep cliff which retreats over time

Formation of a wave-cut notch

Destructive waves erode the base of a cliff, undercutting it to form a wave-cut notch

Formation of a wave-cut platform

The cliff collapses due to undercutting, retreats inland and leaves a flat wave-cut platform at the base

Formation of a cave

Waves exploit cracks and joints in a cliff using hydraulic action and abrasion, enlarging them to form a cave

Formation of an arch

Continued erosion enlarges a cave until it cuts through the headland, forming an arch

Formation of a stack

Weathering and erosion weaken the arch roof until it collapses, leaving an isolated stack

Formation of a stump

The stack is eroded at the base and collapses, leaving a low stump visible at low tide

Formation of a beach

Constructive waves deposit material as their swash is stronger than backwash, building up a beach

Formation of a spit

Longshore drift transports sediment along the coast and deposition occurs where the coastline changes direction, forming a spit

Formation of a bar

A spit continues to grow across a bay until it joins the opposite headland, forming a bar

Formation of a coastal erosion sequence

Caves form first from erosion of cracks, then arches, followed by stacks and finally stumps as erosion continues

Formation of longshore drift

Waves approach the coast at an angle, moving sediment up the beach by swash and back down by backwash in a zig-zag motion

Formation of a concordant coastline

Rock layers run parallel to the coast, meaning erosion is limited until softer rock is breached