2.b - FLAM HEAD CS Flashcards
what type of coastline is the yorkshire coast?
discordant
at the southern end, there is a large chalk headland
then there are sandstones, shales and limestones.
meaning that there are bands of harder and softer rock, lending themselves to the formation of bays/headlands
significance of geology at yorkshire coast
geology will be a long term and permanent factor influencing the landscape that will determine the rate at which marine processes can occur.
how is wave energy influenced by wind at yorkshire coastline?
the winds blow from the north meaning that there is a large fetch of 1500km , as a result the waves have a high energy therefore are mostly destructive
longshore drift moves sediment from north to south
how does wind and wave energy vary on the yorkshire coast?
the winds and therefore the wave energy will vary from day to day (diurnally)
and from summer to winter (seasonally).
most days the wave energy will not be very strong and there will be relatively low levels of erosion and therefore change to the landforms, but then storms could bring very high levels of energy, causing rapid change in short periods of time, mostly the winter.
where is sediment supplied from at the Yorkshire coast?
- as sea levels rose during the last ice age, material was moved onshore (in the same manner as a barrier beach). clearly this input is historic and is no longer happening, therefore sediment being removed will not be getting replaced by this.
- erosion of chalk, sandstone, shale and limestone cliffs. this is ongoing, the rate of input depending upon geology and wave strength.
- the river Esk deposits sediment (but due to it being a heavily managed river, this is minimal).
LANDFORMS - saltburn to Flamborough head
high wave energy along a 60km long coastline in yorkshire
LANDFORMS - geology of the yorkshire coast
mainly of sandstone, shales and limestones formed during the jurassic period as well as some Carboniferous
LANDFORMS - yorkshire coast fetch
the dominant waves affecting this coastline are from the N and NW with the distance of open sea greater than 1500km
LANDFORMS - erosion rates at yorkshire coast
the rates vary along the coast from 0.8m/yr shale and chalk to 0.1m/yr
LANDFORMS - flamborough head
large chalk headland.
the cliffs have till on top, a superficial deposit left behind by glaciers during the Devensian glacial period
LANDFORMS - sediment sources at yorkshire coast
nearshore - driven onshore as sea levels rose at the end of the last glacial period
cliff erosion - sandstone and chalk, boulder clay and gravel
river esk enters at Whitby - this supplies only limited sediment
LANDFORMS - cliffs at flamborough
made of chalk, which is physically strong,
the cliffs are high 20-30m and vertical.
however the top of the cliffs (composed of till) are lowered by mass movement to an angle of about 40 degrees
LANDFORMS - cliffs at robin hood’s bay and saltburn
stepped profile due to more varied geology
steeper areas - sandstone and limestone
LANDFORMS - shore platform at robin hood’s bay
typical angle of 1 degree and maximum width of 500m
formed within the last 6000 yrs
relict feature
LANDFORMS - filey bay
eroded into weak Kimmeridge clay
more resistant limestone and chalk either side forming the headlands
LANDFORMS - beach at saltburn
it has a net increase of sediment of 9245m3 between 2008 and 2011.
a rare example along this coastline as the waves ususally erode sediment before accretion (accumulation) can take place
LANDFORMS - robin hood’s bay
eroded into lower lias shales.
with stronger bands of sandstone to the north (ness point) and south (ravenscar), forming the 2 headlands
how will the cliffs at Flamborough change over time?
lower part is strong rock with tightly bonded material
slow to erode via marine processes
cliff collapse is most likely in stormy weather
the upper half of the cliff which is weaker will see a lot more biological weathering and mass movement (slumping/slipping) more regularly
erosion here will happen more extensively in the winter compared to the summer
how will the cliffs at Robin Hood’s Bay and Saltburn change over time?
there are horizontal bedding planes here with stronger rocks interspersed by weaker rocks
the weaker rocks will be subject to more weathering and erosion therefore slumping is more common, making the angle of cliff not as steep
these will retreat more quickly than the Flamborough Head cliffs
erosion here will happen more extensively in the winter compared to the summer
how will the shore platform at Robin Hood’s Bay change over time?
probably formed over the last 600 years, but as a shore platform grows, it acts as its own breakwater
therefore waves will erode the shore notch, making the platform bigger at a slower rate
as a result, this shore platform will not be growing quickly, unless sea level rise means that the waves can reach the base of the cliffs more regularly
how will Filey Bay change over time?
the bay will be accumulating sediment during summer constructive wave periods
but will be losing sediment in winter months due to winter storms and destructive waves
a dynamic equilibrium will exist, which will keep the beach roughly the same size
how will the beach at Saltburn change over time?
it has a net increase of sediment of 9245 m3 between 2008 and 2011
it will be losing sediment in winter months due to winter storms and destructive waves
how will the green stacks pinnacle change over time?
over time, a stack will collapse to form a stump
most likely during a winter storm after years of erosion
how will the arch at selwick bay change over time?
arch will eventually collapse to form a stack