C 1.1 - 1.5 Flashcards
Zavodovski Island
- uninhabited active volcanic islands in the south Atlantic
- worlds largest penguin colonies
- 36 hours away from South Georgia islands
- 33ft cliffs with 15ft waves
Coastal plains
- land gradually slopes
- deposited sediment eg, sand dunes/ mudflats/ beaches
- sometimes called alluvial coasts
Primary coasts
- dominated by land based processes eg, deposition from rivers/
- new land formed by volcanic lava
Eg, zavodovski island
Secondary coasts
- dominated by marine erosion/ deposition
Eg, slapton
Wave formation
- initially in open water, as energy transferred from air to water
- seabed increases friction and wave breaks
Wave action
- constructive vs destructive waves
- longshore drift moves material along
Sediment systems
- waves break, but vary between high and low tide points
- but can be exceeded by storm waves
- also sea level can change
Coastal defences
- disrupt physical geography processes (latitudinally) eg, walls, or longitudinally eg, groynes
Rock breakdown
- biological/ chemical / physical
- could lead to erosiom
Sediment systems
- material is eroded
- transported along
- deposited elsewhere
Waves are
- Energy moving through water
- waves move up and down in circular/ elliptical orbit
What constitutes wave ‘size’
- strength
- duration
- depth
- fetch
- direction
Wave formation
Shoreline/ seabed
- friction with seabed means water movement slows, wave length decreases and wave height increases
Swell waves
- windless day after a storm
- still, large waves as earlier waves make their way onshore
Constructive waves
- low height, long wavelength 6-8 per minute
- uninterrupted swash, starts at nearshore
- stronger swash than backwash results in sediment berm
- shingle beach has percolation, so less backwash, so steep beach
Destructive waves
- high height, short wavelength 13-15/min
- slower waves approach steep beach
- still circular motion, so mass of wave goes down onto the beach
- Sandy beach has less percolation, so stronger backwash
Coastal morphology definition
- is the study of natural processes ongoing at the shoreline and of the impact due to human interventions within the coastal zone
How can types of waves change over time?
- seasonally - summer = constructive, winter = destructive
- daily - plunging waves become swell waves
- annually - reduced river sediment - building of dams
- coastal management- restricts supply of onshore sediment
- climate change - storms bring destructive waves
Chesil Beach
- shingle barrier beach
- formed by marine transgression (sea level rise)
- 15 metres high
- exposed to English Channel and North Atlantic Ocean
Percolation
Water infiltrating gaps in sediment
- How water permissible is the sediment
Cork coastlines
- limestone/ sandstone
- 90o parallel geology
- some detached islands
What’s the reality of predicting impact on coasts?
- chaotic determinism
- so many different bits of landscape in terms of statistic likelihood’s
- what happens when statistical likelihood forced to work together
- chances of landscape existing the same elsewhere = very close to 0
What did William Morris Davis believe?
- landscapes are ‘uplifted’ by tectonics
- erosion cuts down into the landscape in a four stage model: youthful, mature, flat peneplain, then uplifted again
Walter Penck theory
- uplift and denudation happen at the same time, but come places have rapid uplift, some lower