2.b. CASE STUDIES: Saltburn-Flamborough head + Rhone Delta Flashcards
where is SB-FH
- NE england
- Yorkshire
- 60 km coastline
FH is south of SB
energy in SB-FH
Dominiant waves - N > NE , fetch over 1500km
most exposed area is the N facing coastline (eg nearest to Salt Burn)
waves often exceed 4m (even in summer) = No LSD associated / drift aligned landforms (eg spits)
LSD from N > S
sediment interrupted by headlands causing sand and shingle to accumulate in bays and create beaches (very few well developed)
physical factors which affect the formation of landforms within Saltburn to Flamborough Head.
geological factors, wave action, and longshore drift.
what is the geology of Saltburn to Flamborough head?
- Flamborough head is a large chalk headland (resistant rock) (less than 0.1m/yr erosion)
- The differences in rock resistance create a varying coastline;
with softer clay rocks eroding more quickly (0.8m/yr). This difference in erosion rates creates a stepped cliff profile - Weaknesses in the chalk, like vertical cracks or fault lines, are more susceptible to erosion, leading to the formation of caves and arches
What is the wave action like at Saltburn to Flamborough head?
- High Energy Waves:
The North Sea = high energy waves, [esp. during winter storms.] These waves erode the coast, particularly at the foot of the cliffs, removing clay in suspension
2.Wave Refraction:
Wave refraction concentrates waves on headlands like Flamborough Head, which can lead to the formation of caves, arches, sea stacks, and stumps.
3.Destructive Waves:
Destructive waves, common in this high-energy environment, erode beaches and cliffs.
what are the sources of sediment for LSD and how does the LSD in this area affect the coastline?
Saltburn to flam head
- sediment sources:
cliff erosion, primarily of sandstone, chalk, and boulder clay - Beach and Bay Formation:
The interaction of waves and longshore drift can create bays and beaches, as well as spits and other depositional landforms.
examples of beaches and bays in Saltburn to Flamborough head
- Robin Hood’s Bay:
This bay is cut into weaker shale, creating a beach with a rocky platform where cliffs retrea
2.Filey Bay:
This bay is formed where weak kimmeridge clay meets the coast, resulting in a more developed beach
3.Flamborough Head:
This headland is a resistant chalk formation with bays like Thornwick Bay and Selwicks Bay featuring high cliffs, rock pools, and scenic views
the interrelationship of a range of landforms within the characteristic landscape system saltburn to flamborough head
- Headlands and Bays:
The discordant coastline creates headlands such as that at flamborough head (resistant chalk) with deep bays on eitherside created by the erosion of clay as well as bays such as filey bay and robin hoods bay due to being made up of weaker shale. - Wave Refraction:
Wave refraction concentrates wave energy on the resistant chalk headland, = caves, arches, stacks, and wave-cut platforms.
4.Wave-Cut Platforms:
The relentless erosion of the chalk creates a wave-cut platform at the base of the headland, which is exposed at low tide.
Cliffs + landforms on headlands
- cliffs:
- horizontally bedded strata = shore platforms
- chalk = sedimentary = resistant - Landforms
- materjoints in chalk have been exploited by wave action = chalk + boulder clay collapse into underlying sea caves leaving tunnel shapes deppressions on cliff top = Blowholes
name examples of the drivers of millennia -scale changes as well as the drivers of short term changes.
Millennia-scale:
glacial activity, Erosion and Deposition, Rock Resistance.
short-term:
Wave Action, Landslides, Human Impact.
explain each driver of long term change.
- Glacial Activity:
Glaciers deposited soft clay and shaped the landscape during the last glacial period, leaving behind features like cliffs and headlands. - Erosion and Deposition / rock resistance
The soft clay cliffs erode rapidly, = bays and depositing material along the coastline = beaches
explain each driver of short term change.
- Wave Action:
Waves erode cliffs, transport sediment, and sculpt the coastline through processes like abrasion, hydraulic action, and solution
2.Landslides:
Clay cliffs are prone to landslides, particularly after periods of heavy rainfall, which can dramatically alter the coastline.
- Human Impact:
Coastal management structures like seawalls and groynes can impact natural coastal processes and the landscape.
where is the Rhone delta
- River Rhone flows into the mediterranean (west of versailles in S. France)
- delta lies between 2 major distributaries of the river rhone:
Grande Rhone (85%) + Petit Rhone - 30Km from coast keeps splitting
energy in the rhone delta
- The most frequent waves are from the southwest (30%), but they are relatively low in energy. (0.5-1m height)
2.Waves from the southeast (16%) and east-southeast (11%) are less frequent but higher in energy. (2m height)
- winds from SE whose speeds can exceed 100km/hr
- short fetches (enclosed med) longest is 900km from SW = short low energy waves
physical factors which affect the formation of landforms within the Rhone Delta.
- high levels of deposition from rivers = gently sloping lanscape = absorbs wave energy
- low tidal range
the low tidal range (around 30 cm) = less significant impact on landform formation compared to river and wave action
Landforms along the rhone delta and why they are formed
- Gracieuse Spit - SW - NE LSD [cell 1]
- Onshore Bars;
Converging LSD currents [cell 3] - lagoons ;
LSD has moved sand to create lagoons trapped behind onshore bars and spits - Longshore troughs;
in the near shore area there are lonshore bars where backwash removes sand and deposits; inbetween these are longshore bars - Marshes;
salty sandy marshy areas colonosed with brackish plants adapted to salty conditions.
reasons for deposition
rhone delta
- Sediment accumulation at the river mouth creates the delta, a triangular-shaped area where the river meets the sea
2.The river divides into multiple channels, each contributing to sediment deposition and shaping the delta’s morphology
3.Coastal Processes:
Wave and wind action, LSD, tidal influence these all affect the transport and deposition of materal responsible for various landforms
the interrelationship of a range of landforms within the Rhone delta
Spits and Bars:
Spits, formed by longshore drift, trap sediment and create lagoons behind them. Bars, also formed by longshore drift, can alter wave patterns and affect erosion rates.
Dunes and Lagoons:
Dunes, formed by wind, can stabilize the coastline and protect against erosion, while lagoons are important habitats for wildlife and can also be affected by coastal processes.
when did the delta begin to form?
over the last 7000 years when sea levels began to rise at the end of the last ice age.
what did human management do?
human management has moved the mouth of the Grande Rhone reducing it from three to two [19th cent]
what is the size of the delta?
total length of the coastline is 90km and covers an area of 1740km
how are dunes formed? (the Rhone delta)
dunes form when:
1. wind blows from the sea and dry sand is moved up the beach by saltation
2. sand becomes trapped. by obstacles on the berm of the highest springtides
3. gradually these sand deposits build up and become colonised by plants
[ such as Maram plants, which are adapted to salty conditions, and have long roots to help survive shifting sands]
4. these grasses trap more sand forming an embryo dune. these grow to form a ridge.
5. overtime these dunes stabilise and plants change.
name examples of the drivers of millennia -scale changes as well as the drivers of short term changes.
Millennia-Scale Changes:
sea level fluctuations, river sedimentation and human intervention
short term:
Rapid Erosion and Deposition, Channel Changes During Floods
explain each driver of long term change.
As sea levels rose, the delta expanded, and land previously above sea level became submerged or marshy
The Rhône River has been depositing sediments in the delta for thousands of years, building up new land and shifting river channels. These sediments, ranging from silt to sand, create distinct landforms like prodeltaic lobes and spits
Over time, human activities like dyke construction, dredging, and dam building have altered the natural flow of the Rhône River and its sediment load, impacting the delta’s morphology.
