welcome to eq one of our landscapes and change so this is the first section of the coast topic that you studied in year 12 and eq1 asked why are coastal landscapes different and what processes cause these differences um reminder as with all of these recordings that this is not replacing what you have done in lessons when you did this topic this is just to reinforce the main ideas behind the topic and is good use as a revision summary for the entire topic today we're going to look at just eq1 and you can use the coast revision booklet that you've been given along with this to help you so the first thing we looked at in coats is the shoreline and what we call the littoral zone now the littoral zone is very simply the breakwater area this is where the waves come on shore it's the nearest to the coastline where high and total high and low tides happen so there are four main sections if you like to the littoral zone there's the offshore section this is the farthest section of the littoral zone out to see and this is the deepest area where waves start to break then we've got the near shore which is closer to the coast and this is an area of shallow water and it's beyond the low tide mark so there is more friction in this area between the seabed and the waves and that distorts those waves it's the brake zone then we've got the four jumps for shore zone now the fortune is the area between high and low tides so this area is covered in water during the high tide and then it is exposed as you can see in the image there during low tide and then the back shore is the area above the high tide mark and that's affected by wave action only during storm events so the back shore may be covered by the sea water during stormy events where the wind is pushing the waves onto the coastline but generally it is not covered by water and then you've got your cliffs and your general posts that we build on behind that now there are different types of coastlines formed by this littoral zone because of the processes of littoral zone because of the erosional depositional processes we get different types of landscapes and we can see that they're different by the formation of rock at them so the first type of coast is a rocky or a clift coastline and these are usually in areas of high shape of the land or high relief usually have resistant rock they are high energy environments and erosion in these places is greater than deposition and you usually find destructive waves at these types of coastlines and you can see there in the image on the bottom left the type of clothesline we're talking about here so even though erosion rates are high erosion overall actually takes a long time for this type of rock then we have sandy coastlines now these are generally at low relief areas they're gently cloping there's soft rock here deposition is greater here than erosion so there's lots of deposition taking place by the coastline by the sea because of constructive waves so they have a strong swash and a weak backwards then we have estuarine coastlines now these are low relief coastlines with salt marshes as you can see in the image there the reason they are estrobin is because they usually are at a river's mouth so deposition is also greater than erosion here and it's a low energy environment with solved and there's one thing to consider all of these types of coats lines and that is the dynamic equilibrium of the coastline balance between the inputs of sediment the output and the flows of sediment that exist because of the energy that exists at the coastline so we can also see longer term changes at coastline such as sea level change and sea level rise and that also affects the the balances or the dynamic equilibrium between the inputs flows and outputs and you could also factor in more local changes like high and low tides weather conditions varying wave energy as impacting on that dynamic equilibrium at a coastline now we can classify coasts in terms of short-term and long-term classifications so let's start with the short-term classifications of pokeslands so things that happen in the short term is tides from energy inputs so the ebbs and flows the highs and lows of those tides over a 12 and a half hour period during the day as well as current type and river flows and the amount of precipitation and gravity and tectonics and the change of those and that creates our high and low energy coastlines overall we've also got sediment inputs over the short-term classification period the deposition and erosion rates if the deposition rate is higher at a certain point in time that means the coastline is expanding it's growing in size if erosion rates are higher that means the post line is receding it's eroding in that short period of time and linked to that we've got advancing and retreating post lines so erosion and deposition affect whether a coastline advances or retreats and that also impacts whether the coastline is emergent or sub-emergent and that's linked with sea level rise 2. so if the sea levels rise dramatically you may have a submergent coastline if the sea level is not rising dramatically you may have an emergent coast so long-term classifications now so longer term things at a coastline which can classify that coastline are the geology or the lithology so the lithology is the rock type at a coast and the structure of that rock the way in which they're arranged affects what type of coastline it might be so this is mainly used to determine whether a coastline is rocky sandy or esterine which we mentioned earlier so the actual lithology at a coastline will determine if it's hard rock for example it's probably a rocky coastline or if it's softer rock it's probably a sandy coastline or if there's a river it'll be estuarine and we've also got to consider concordant coastlines and discordant coastlines so concordant coastlines are where the rock runs parallel to the sea and discordant coastlines are where the rock is perpendicular in bands to the sea we've also got longer term sea level changes in sea level rise so as i said before this is used to classify emergence and submerging coastlines and tectonic plate shifts and movements can also help pacify but climate change in recent years has been a big factor in classifying coastlines and so as climate change continues and as sea level rise continues we may see more and more submerged coastlines over time so we've got two types of coasts here a rocky coast and a coastal plain now rocky coasts make up around 1 000 kilometers of the uk's coastline and they are mainly in the north and west the cliffs there vary in height from very high cliffs in scotland and the west of scotland to lower relief cliffs in cornwall in the southwest the geology in these places is very resistant so the rocks are very resistant and they erode very slowly and there is little deposition but there is high energy erosion so erosion is constantly taking place but as we know because the rock is a hard type of rock it takes a long time for that rock to erode and there is therefore also little sediment to deposit now in a sandy plain as you can see in the image on the bottom right here we mainly have a flat or gently sloping relief type of coastline and it often contains wetlands and salt marshes too these are low energy environments so there's no erosion rates but deposition rates are high they can be sand they can be shingled or they can be cobbled stones as well and this is most of the uk's coastline in the south and east of the uk so places such as the south coast particularly around swannage is this type of coastline it's a sandy plain photon i mentioned earlier concordant and discordant coastlines key thing to remember with a concordant post line and you can draw this so you can remember it is that the rock runs along the coastline not in bands as you can see here on the left hand side in one consistent band so we've got limestone here which is a hard type of rock along the coastline here and that runs directly along the coast for example in georgia in the south west one continuous layer of hard rock protecting the softer rock behind it whereas a discordant coastline is these differing bands along the sea of hard and softer rocks so clay in sandstone or plain limestone so this is most of the east coast which is a lot of our case study and that's holderness and this is differing layers of resistant and soft bands of rock and we know that the softer bands of rock here for example the clay as you can see will erode much more quickly than the harder bands of limestone so the clay forms bays and therefore sandy posts and the limestone and sandstone formed headlands because of the harder rock and we've got other portland examples of coastlines and you can see in the images here on the right we've got the dalmatian coastline of croatia and on the bottom right here we've got half coats lines which form essentially bars along the coastline because of the sands deposits so a dalmatian coast like in croatia is actually uh a coastline that has formed because of what are called anti-climes and sink lines which are ridges and valleys they've been formed over millions of years due to the harder rock that you can see on the image or the satellite image here on the right and also what's happening is this coastline is submergent so we are seeing the harder higher bands of rock left over after sea level change and that's why you have these patterns of smaller rock islands remaining so sea level rise has left what's behind as you can see in the satellite image there are lines of islands that are essentially separated by narrow bands of c so that's an example of another concordant coastline and we've also got half coats lines now this occurs where deposition produces what's essentially unconsolidated material so unconsolidated rock so what we have is essentially a ridge and that sand ridge forms over bays as you can see down here we've got the curonian spit that connects the zambian peninsula to lithuania and this is the norman half and that connects lithuania to russia and so what's happened is deposition over time interglacial and glacial periods too have contributed to the amount of sediment that's being deposited in this area and that's connected the lithuanian coastline to the rochim coastline through the spit turning into a bar we've also got to consider the influence of coastal dip on the rock structure and the layers of rock so dip is the angle of the rock from horizontal it's a tectonic feature mainly and what happens is it produces different types of dips so a horizontal dip produces a vertical or near vertical profile of the landscape a high angle of seaward dip which is over 45 degrees which produces a slow low sloping angled profile with run lock fade one lock facing the sea these are vulnerable coastlines and are vulnerable to be attacked by subaerial processes and weathering lootens the strata in the rock here whereas we've also got a low angle of sea wood dip which actually produces a steeper profile of the rock which may even exceed 90 degrees this as you will see produces major cliff collapse so if we think about our undercutting of the rock that's the type of coastline we're thinking about here and there is marine erosion taking place which creates that overhang and so the cliff is constantly collapsing collecting into the sea we've also got to consider the actual structures of the rock and cliff profiles themselves so in rocks we get what's called faults now faults are like major fractures created by tectonic plates they create a fault line they increase the rate of erosion and this leads to rocks easily being eroded over time we also got joints in rocks and these are fractures without the rock being moved so these are fractures not like folds the rock has not been moved by tectonic plates here this is because of weathering okay and compression so these occur in most rocks and they can be seen as block types of rocks and you can see them in the image here on the right hand side you've got these block type structures in igneous rock they can form during magma cooling and in sedimentary rock they can form through the compression and the stretching of the rock sitting on top of each other in layers over time we've also got fissures these are more open than fractures so these are more open than joints and faults and can be found as a characteristic of most rocks on the earth's crust so fissures are very deep open ravines in rock they're deeper than joints and faults and finally we've got the folding that can occur in rocks and these are bends that occur in rock and you can actually see these bends in the image on the right hand side here these bends produce basically a layering effect and the main type of that layering we can see at coastlines is an anticline and a syncline folding pattern now anticlines are when the folding is awkward and zinc lines are when the folding occurs downward now rock type in bedrock at the sea is really important so the rate of coastal recession or retreat is influenced by rock type is influenced by how reactive the rock is to chemicals whether it's a less resistant type of rock or a more resistant so a less resistant type of rock might be considered plastic a more resistant type of rock might be considered crystalline and whether the rock has any cracks or faults or fissures etc that we've just looked at previously so all of these rock types have different weaknesses to them or strength in terms of erosion and coastal recession so let's start with our igneous rock type so types of igneous rocks include granite and dolorite and battles now igneous rocks erode very slowly and they also weather very slowly because the crystals within them are interlocking so they form these x-like shapes act like shapes of bands so they bind together so they're more resistant and they contain very few joints and weaknesses so these are one of the hardest and most resistant types of rocks because of the way in which they have formed we then got metamorphic rocks so they are things like marble and slate and chest now these have recrystallized or reformed through heat and pressure from deep under earth in the mantle they have a crystalline structure that are made up of these crystals which means that they are resistant but they are less resistant than the sedimentary rocks we're about to consider because the crystals form in the same direction so they are not interlocking so they're just in a horizontal fashion then we've got sedimentary rocks and these are things like sandstones and limestones and clays and these are formed by compression and compaction over millions of years these are the least resistant type of rock because they are heavily daunted so they have lots of joints and cracks in them and they have weak structures they have moderate erosion rates in the sense that they do erode over time but they rolled faster than atheist rocks and they are all rerolled slower although sorry they also rode faster than some types of plays but they do include clay as well so because there are different types of plays the erosion rate of those clays actually differ and vary over time and then we finally got unconsolidated sedimentary material and this one's easy this is just alluvium this is just not yet cemented or compacted sand and other types of rocks these are very easily eroded at around two to ten meters per year that's just a brief summary of how hard and soft each rock type is now these rock types affect the types of cliff profiles we get so less resistant layers or bands of rock or strata erode quick quickly and weather quickly and they produce things like wave cut notches because of the marine processes on the rock resistant rocks erode slowly in weather slowly and they form what's called a bench at the cliff base and this leads to an overhang of the cliff above essentially what we've got there is undercutting taking place so wave cut platforms is what that bench would look like so we've got to also consider whether rocks are permeable or impermeable non-permeable so permeable rocks are those that allow water through them because they're porous they have pores like chalk and they may also have numerous joints permeable rocks tend to be less resistant because weathering can take place on them much easier so limestone for example weathering can take place at a fast rate and some types of granite like feldspar can also take place at a higher rate now non-permeable rocks which are rocks that do not let water travel through them erode much slower than permeable rocks okay they're harder material we've also got to consider our coastlines the role of vegetation vegetation is very important to a coastline i'm just going to let you take 10 seconds to have a look at the image on the right hand side here to show you the species of plants you may find at coastline okay so we know that vegetation stabilizes the coast because the plant roots bind the soil together and that leaves the stems and the leaves to cover the surface of the ground and protects it from long-term drift and wind road erosion and tidal erosion cokes are very harsh environments for plants because of high winds because of the lack of shade because of the salt water because of the sea submerging them plants have to adapt to the coconut pioneer plants which you can see in the bottom of the image towards the coastline here where the waves will interact with those plants are the first type of plants to colonize our coastline they modify the environment by stabilizing the sediment they add nutrients to the soil and they reduce evaporation rates because they need that water to grow and then they create what's called plant succession and as you can see in the image the further you go back towards the coast where we live the more types of different plants and communities you will find and the stronger and more stable those plant communities will be because they're less exposed to the water themselves and that leads us directly onto sand dune succession or the summer sea now sand dunes succession is all about how the sand dunes form stronger binds with sediment and with plants the further away from the water at the beach you are so we first got embryo dunes now embryo dunes are the smallest types of dunes that form at the coating they have pioneer plants and types of grasses in them and these have to form around a large block of sediment in some way and they alter the conditions that other plants can tolerate so they colonize and they form a4 dune over time now four dunes are slightly stronger than embryo dunes and as you can see in the image here 400 dunes for more grasses they have a higher relief rate and then as you go further back again the plants get stronger the june stabilizes further and we get a second type of tune we get a stronger taller dune and that might be a grey gym and then we go even further back to the rear dune and this is where we get the forest this is where we get trees and large shrubs and these are the strongest type of dune they are very well sheltered from the coastline because the second and four dunes gel to them so they take most of the battering from sea waves and wind from the coastline as well and what we essentially get over time as we move further away from the shoreline further away from the four zone is we get stronger and stronger sand dunes we get a climax in the plant's community so equilibrium between climate and soil is reached so that is the summer sea of sand dunes succession but we've also got salt marks marsh succession as well or what's known as italicia and the mixing of fresh water and sea water at the coastline or an estuary coastline causes the clay and the sand to stick together and sink and what we get is over time we get a salt marsh formed through that mixing of clays and fresh water and sea water we can also get the salt marsh drying up where it's no longer provided water over time and this means that these salt marshes can actually form as you can see in the image down here uh sea lavenders and cord grass and other types of smaller plants and these plants again very much like with um sand dune succession form stronger over time the further away from the coast you go oil fertility also improves the further away from the coast you go as well and when all the rain water washes out all of the salt on the salt marsh this is when we allow plants to start colonizing in a more strong way compared to under the sea in the uk uh the climax community is normally deciduous oak forest before this point away from the sea and in scotland particularly it is coniferous pine forest now that is a brief roundup of everything in eq1 for coastal landscapes and change the key thing with eq1 is that it's mostly theory based and it is just general knowledge so what you need to do is make sure that you go back over this numerous times that you look at sanji and succession and salt marsh succession and that you look at the basics of rock lithology the basics of how rocks are formed and the weaknesses and strengths of those rocks at different course i hope that was useful for you in some way the next section will be on eq2 and that will be looking at the characteristics of landforms at coastlines please do use your coast revision booklet to go over these sections of post landscapes and change and i will see you in the next one