Coasts

randomfella

Coasts

Spit – e.g. Rosslare Point, Co. Wexford
A spit is a feature of marine deposition, formed by the action of longshore drift. It is a projecting ridge of material, which is attached to the mainland at one end. The seaward end is often curved due to wave refraction. A spit may also extend partially across and estuary of a river.
Longshore drift moves material along the coast in a zig-zag fashion. Waves approach the shore at an angle and as the wave breaks, it carries material up the shore at the same angle while the backwash, and any material it is carrying, return down the beach at right angles. The action of swash and backwash allows longshore drift to move material along the coastline. This continues until there is a major change in the direction of the coastline such as an estuary or the entrance to a bay. A spit will develop where the change occurs. Marram grass colonises and helps to anchor the spit. Sometimes sand dunes may develop on the landward side of the spit.

Headland and Bay – e.g. Galway Bay, Co. Galway
Along a coast, areas of alternating hard and soft rock are to be found. These are attacked by the combined processes of erosion, and soft rock is worn away and develops into a bay leaving the more resistant rock as an outcrop or headland. The coastline is attacked by the processes of hydraulic action, abrasion, compression and solution. During storms, waves exert considerable energy on rocks. This weakens and sometimes crushes the rock. Air is trapped and becomes compressed in joints in the rock. This increase in pressure will weaken and may break off pieces of soft rock. The most effective process in the formation of bays is abrasion. This is the sea armed with sand, stones and boulders lashing the coastline. The process of solution has a role to play in the formation of bays, as sea water is able to erode certain rock types. Limestone, which is well jointed, is vulnerable to sea water. Bays are funnel shaped due to the reduction in wave energy. This reduction is best illustrated by the presence of a beach at the head of the bay (a bay head beach).

Cliff – e.g. Cliffs of Moher, Co. Clare
As a new land surface is exposed along the coast, it is attacked by marine erosion at high tide level. As water lashes the coastline, the process of hydraulic action i.e. the sheer force of the water, erodes the land surface. The process of compression is also active at this stage. Compression assists the erosional process. Breaking waves compress air in cracks in the rocks. The air expands explosively as the waves retreat and rocks shatter. The cracks and lines of weakness are enlarged until a notch develops. The process of abrasion now increases in importance as the sea’s load increases in amount. Sand, pebbles and boulders crash against the coastline. The notch increases the height, width and depth. Eventually the unsupported material above the notch collapses and forms a cliff. Over a period of time the continuous formation of notches and undercutting leads to a retreat of the cliffs and the formation of a wavecut platform. The wavecut platform gently slopes seawards. As it grows wider there is a decrease in the erosive power of the sea. Eventually marine erosion will cease and the cliff retreats in response to other agents of denudation such as freeze thaw action.


JUst wondering what do i need to add to this to get an A?
What are u studying for part (b) ?
I'd love for the changing sea levels to appear but doubt it.

Con9903

Does it matter if you do all erosional or all depostional features. I've only learned depositional features for karst.

As for the case studies, I just read through general nots on that highlight relevant bits. Then in the exam you can bull**** your way through, in a question like "how have humans attempted to control sea action" or something like that

randomfella

Con9903 wrote:

Does it matter if you do all erosional or all depostional features.

well the 'recommended answer is 2 erosion and 1 deposition' i'm sure they can't dock u but the 2 differnet features give u more scope. For instance in coasts if i wanted to do another erosional feature say sea stack etc. i will be repeating the processes.

Rredwell

I think those answers would merit an A-grade.

Did you get the Mock question (b) on changing sea levels?

randomfella

Rredwell wrote:

I think those answers would merit an A-grade.

Did you get the Mock question (b) on changing sea levels?

Yea.
it goes something along the lines of....

ria (bantry bay, Co. Cork)fiord (Killary,Co. Galway) discordant features dalmation coasts (Yugoslavia), raised beach(courtmacsharry, cork) concordant- were my features.
Happened at the end of the pleisotene (sp?) ice age.
Isostatic - movement of the land up. The ice had compressed the land down and when the ice melted, the weight lifted up off the ground and it rose
Eustatic - glaciers melted turned to water - sea level rose.
or water turned to ice, sea level lowered.



Limestone, chalk, Boulder clay - Fanore, co clare, granite(feldspar) are vulnerable to solution.
52% of waterford's coastline is soft, erosion rates of 1.8% have been recorded per annum.


HUMAN INTERFERENCE
destructive/constructive
sea walls, placing of large boulders along sea walls, placing of Gabons,wire baskets filled with stones along the coastline (e.g. Lahinch, co Clare)
Sand dunes - marram grass and coniferous trees planted on them to stop them endangering agricultural land or there migration inland (Inisheer, Aran Islands)
Groynes or barriers at right angles stops long shore drift. (youghal, co cork)
Sand and shingle used to be used for building material but now local authorities discourage this activity.


Beach nourishment
pumping of sand, increase deposition, offshore dredging, care is taken in grain size, occurs where need for beach facilities, coastal defence work as well as for recreational use.

Tetrapods, artifical sand dunes, plastic sea weed.

Artifical sand dunes - where people have destroyed natural dunes or where there were none in the first place wooden triangular frames are anchored to the beach so that wind blown sand hits them and builds up a dune this can be further stabilised by plastic grass being placed over it.

Tetrapods - kilmore quay wexford to protect pier.

randomfella

i can't draw a spit. Anybody know how, and also how to post up them little pics? the only pic of a spit i have is incredibly bad.

randomfella

bump. Anybody give feedback?

Waltons

Our teacher was saying that it'd be a good idea to define Abrasion, Attrition, Hydraulic Action and Compression at the start of the question so when you need to refer to it the examiner can clearly see about what you're talking (rather than defining it in the middle of an explanation to a feature).
They're good explanations of the features though. I'm doing Cave/Arch/Stack and Cliffs for erosion and beaches for deposition (I can't stand doing spits, personally. Never got the hang of it).

The answers for the B parts are really good, a lot of things that could be asked are answered there. You might want to do a bit about Constructive/Destructive waves on the main features, but overall it's nearly perfect.

randomfella

Waltons wrote:

. You might want to do a bit about Constructive/Destructive waves on the main features, but overall it's nearly perfect.

not really sure what u mean here?

We were told to stay away from sea arch, stack, stump etc. don't know why.

Do u think i should mention tombolo and lagoon etc. to stretch out answer on spit?

Thanks for ur feedback waltons always appreciated!

Waltons

Constructive waves are low frequency (the don't hit that often; 6/8 waves per minute) waves that deposit more than they erode. They tend to be relatively small because there isn't a large length of fetch over which they build up.
Destructive waves are basically the opposite. They occur very frequently; 12/16 per minute, they erode far more than they deposit and they're very large waves due to their large length of fetch.

I've prepared my cave/arch/ etc stuff already, so I'll be putting that down
And, yeah, if you have time put in the tombolo and lagoon, but only if you have the time to spare. They're not necessary but if the examiner's looking for marks to bring you up a grade and you've put in extra features with the physical it'd certainly be to your favour.
On a side note, if you're nearly up to the next grade level, the examiners apparently look mostly in the Regional essay to up you but, as I said, if you've the time to put in some extra (RELEVANT) stuff in your physical section it definitely wouldn't hurt!

randomfella

Waltons wrote:

On a side note, if you're nearly up to the next grade level, the examiners apparently look mostly in the Regional essay to up you but, as I said, if you've the time to put in some extra (RELEVANT) stuff in your physical section it definitely wouldn't hurt!

thanks for the explanation of the waves.

Yeah thats cool about the regional being the thing they check to up your grade. I always get an A when i do Italy so that should be fine. I'm really hoping for an A, got 82 in mocks and it would take a weight off my shoulders with regard other subjects. DId u see my italy notes? Its basically what i'm going to write except in point form, do u think that is A standard or is there anything i need to add, bear in mind i prob won't be including the Alps unless it states 3 or more regions.
I heard that quick analytical sentences help raise your mark.

colin300

Does anyone have any notes or anything on role of the sea or any notes on wht might come up in a part 2 of any question?