Coasts 6 Markers (2) Flashcards
Using Figure 6a, Figure 6b and your own knowledge, asses the potential impact of these changes on coastal landform development in this area.
It is evident from figure 6a that 20,000 years ago much of the north of Europe and northers Asia was covered with ice. The north of Britain and Ireland were as well effected. Correspondingly sea levels appeared to be much lower creating large areas of land, for instance across what is currently the North Sea, which no longer exist today.
Figure 6b demonstrates that this land is now submerged. The land bridge connecting the UK to Ireland and mainland Europe as well is submerged.
Following the eustatic sea level rise submergent coastline features (fjords, rias, drowned river valleys) were formed. For example , fjords were formed, as glacial valleys were drowned. For instance, many fjords can be found on the coasts of Norway, which as it can be seen on the figure 6a used to be ice covered. Nevertheless, following the change in sea levels locally some emergent features occurred. For instance raised beaches, that are areas of former wave-cut platforms and their beaches, which are at a level higher than the present sea level. Raised beaches are common around the coasts of western Scotland and can be found at an elevation of 8m, 15m and 30m, due to differential uplift of isostatic redound which is evident of figure 6b with dark colored area, this are only approximate heights.
Using figure 6 and your own knowledge, assess the role of vegetation in the development of this landscape. (Sand dunes) (2019)
The development of sand dune shown on the figure 6 is dependent on a number of factors, large tidal range, strong onshore wind and supply of sediment to the coast play a vital role in the development of the landform. Large tidal range present on a beach and strong onshore wind allows sediment to dry out and be transported by aeolian forces, saltation or traction to the back of the beach where it is accumulated to form a sand dune.
But vegetation plays vital role in the development of a sand dune, as it can be seen from the figure, foredunes are stabilized by vegetation, possibly marram grass, which binds the sediment together with its roots stabilizing the landform. There is also a present evidence of vegetation succession (psamossere), as dunes in the background are higher (‘rising to hundred meters’) and are covered by numerous types of vegetation, that stabilize the landform and supports its further development and growth, for example from foredunes to yellow and grey sand dunes.
Therefore, vegetation and especially vegetation succession plays vital role in the development of the sand dunes. Nevertheless, such factors as sediment supply to the coast, large tidal range, strong onshore wind are extremely important for the development of the sand dune in early stages.
Using Figure 6 and your own knowledge, assess the view that rock type is the most important factor in the development of this landscape. (2020)
Rock type is a factor in shaping the arch. As initially it is likely that arch on the Figure 6 was formed on the headland on a discordant coastline. Headland was able to form due to the altering nature of soft and hard rock along the coastline, present differential rate of erosion and wave action. This allowed erosive power to be concentrated on the headland.
On the figure 6, destructive waves can be seen. This suggests that it is a high energy coastline with strong wave action possibly due to strong wind and large fetch, leading to higher rates of erosion. It can be argued that present on the rock surface cracks and joints initially would allow hydraulic action to develop and enlarge crack leading to cave creation eventually creating an arch.
Sub-aerial weathering is as well a factor in the development of the arch, as for instance vegetation weathering on top of the arch would allow the arch to become a stuck over time. Nevertheless, rate and type of sub-aerial weathering is as well dependent on the rock type.
Thus, rock type is an important factor in the formation of the arch, nevertheless significance of the high-energy environment should not be undermined. Other processes involved in the development of the arch such as sub-aerial weathering are as well dependent on the rock type.
Using Figure 6 and your own knowledge, assess the relative importance of factors leading to the development of this landform (2021)
A landform on figure 6 is a spit, that is an elongated, narrow ridge of land that has one end joined to the mainland and projects across Humber estuary. Sediment input and operation of along-shore drift are the most important factors in formation of a spit.
Boulder clay as a sediment input is unconsolidated and easily eroded, allowing it to be easily transferred via long-shore drift. When the coastline changes its direction, sediment would be carried into the deeper estuary where it is going to be deposited, with time landform will gain permanence.
Vegetation presence is an important factor in the development of the spit, as roots of vegetation would bind the sediment together, supporting the development of the spit over time. Presence of river action played a role in formation of a spit as river current did not allow the spit to link the two ends of a coastline.
Therefore, sediment input and longshore drift are the most important factors in the initial formation of a spit, nevertheless the development of the spit over time is as well dependent on such factors as presence of vegetation and action of the river.
Using figure 7 and your own knowledge, assess the role of mass movement upon the development of this area of the Holderness coastal landscape.
Figure 7 show ‘terraces’ or ‘slabs’ of cliff that appear to have slumped from the main cliff face. This is likely due to the process of slumping. This would ussually occur where soft, unconsolidated, permeable rock is layered on top of a more permeable rock. Holderness coast is ‘overlaid with unconsolidated glacial deposits’ which are permeable, that lie on top of chalk, which is even more permeable rock type. During periods of heavy rainfall, as mentioned in figure 6 area is ‘prone to heavy storms’ the upper section of cliff becomes saturated, this added weight causes large sections of the cliff to slump and rotate along bands of weakness in the unconsolidated rock.
There is clear evidence that the mass movement process of slumping has a vital role in development of this landscape, to an extent climatic conditions, geology and predominant rock type of the area as well contribute to the formation of the landform as they allow the slumping mass movement to occur. On contrary, hydraulic action and wave action are likely to have limited role in the formation of this landscapes, as based on figure 7 there is a present stretch of the beach in front of the cliff, and thus it is likely that sea would reach the cliff only at high tide.
