14047847
Description
Flashcards by Jan Kowalski, updated more than 1 year ago
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Created by Jan Kowalski
over 6 years ago
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| Question | Answer |
| 4 types of erosion | Hydraulic action, abrasion (corrasion), attrition, solution (corrosion) |
| Hydraulic action | Waves breaking against the cliff by their weight and power |
| Abrasion (corrasion) | Particles carried by waves crash against cliff, eroding it |
| Attrition | Particles carried by waves crash against each other and are broken up into smaller and rounder particles |
| Solution (corrosion) | Acids in seawater slowly dissolve the chalk and limestone cliffs. Material produced is carried away by soultion. |
| Swash | The advance of a sea wave up a beach after the breaking of a wave |
| Backwash | The retreat of a sea wave down the beach after the breaking of a wave |
| Fetch | Distance over which the wind has blown and pushed the waves |
| Constructive waves | These waves are low, have a long wavelength. Low energy waves, strong swash, which deposits material on the beach, weak backwash. Usually associated with beach deposition |
| Destructive waves | These waves are high and steep, short wavelength. High energy waves, weak swash, strong backwash, which takes material back into the water. Usually associated with beach erosion |
| Longshore drift | The zigzag movement of material along the beach due to the swash carrying material an the beach at the angle of the prevailing wind and backwash taking it perpendicularly back to the water |
| Speed of erosion | - softer rocks (easily erode) - stronger destructive waves - no natural/man-made defences against waves |
| Bay | When soft rock surrounded by hard rock headlands erodes and forms a beach by sand depositing on it |
| Headland | The hard rocks jutting into the water from the land after soft rocks surrounding it erode |
| Cave | When waves force their way into cracks in the cliff face, water containing sand and other materials grinds away at the rock until cracks become a cave (hydraulic action) |
| Arch | If a cave is formed in a headland, the waves crashing into it may eventually get through the headland to the other side forming an arch |
| Stack | Ann arch gradually becomes bigger due to waves crashing against it until it cannot support its top. The arch collapses, a headland is left on one side, arch (tall column of rock) on the other |
| Stump | When a stack is attacked by waves, the waves for something similar to wave-cut platforms. This weakens the structure and the stack eventually collapses forming a stump |
| Bar | When a spit stretches across a bay linking two headlands/ Behind the bar an area of water may be cut off from the sea to create a lagoon |
| Spit | Formed when LSD deposits sand when there is a sudden change in direction of coast. It's a long, narrow stretch of sand with one end attached to the mainland |
| Tombolo | Formed when a beach or sand spit joins up with an offshore island |
| Beach | When constructive waves deposit sand on the shore or in a bay |
| Coral reefs | Community of living organisms; formed from the protective skeletons of coral polyps from calcium carbonate |
| Conditions for coral reefs | - warm water (23-25 C best) - Clear, shallow saltwater, not deeper than 50 m - plenty of sunlight to aid photosynthesis |
| Fringing reef | Coral platform grows out to sea attached to the mainland. Shallow lagoon lies above it |
| Barrier reef | Corals growing in shallower area away from mainland. Water between mainland and are where formed is too deep, forms a lagoon. Formed offshore along coastline |
| Atoll | Develop around islands, grow in a circle attached to the land. Sea levels rise or land subsidence causes corals to rise to reach sunlight. Eventually, this forms a ring of coral reefs with a lagoon replacing the island in the centre |
| Mangrove swamps | Areas of vegetation surrounded by salty water |
| Conditions for mangrove swamps | - salty water - temperature remains above 20 C - seasonal temperature range not exceeding 5 C - calm areas, no strong waves or tidal currents |
| Opportunities along coast | - Area flat/gently sloping -> farming - Building settlements/communication - Deep water & shelter from storm -> ports handling imports/exports - Ports -> manufacturing industries - Fishing in coastal water -Attractive scenery/climate -> tourism |
| Hazards along coast | - Storms -> death/injury, damaged property, disrupted communication, threatened livelihood - Lowland areas close to sea -> tsunami/floods -> coastal erosion, homes/businesses/farmland at risk |
| Hard engineering | Man-made LSD and erosion management strategies that tend to be expensive, short-term and unnaturally looking |
| Soft engineering | Natural features developed to reduce LSD/erosion. Sustainable, usually cheap, long-term and naturally looking |
| Sea walls | A wall built on the edge of the coastline that refracts wave energy back away from the coast. Aims to completely block waves and their effects |
| Groynes | Wooden barriers built perpendicularly to the beach. Trap sand to reduce movement of material along the beach due to LSD |
| Rock armour/boulder barriers | Large boulders piled up on the beach. Gaps between them let waves through, but energy of wave is dissipated. Withstand erosion themselves so cliffs don't erode |
| Beach nourishment | Replacing beach material removed by erosion or LSD |
| Managed retreat | Areas of coast are allowed to be eroded and flooded naturally. Usually low value areas. Eroded material encourages development of beaches and salt marshes (natural defence), and doesn't destroy the environment |
| Zone management | Withdrawal or prevention of planning permission for new development (managed retreat) |
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