Transcript Document
Teach me, Tell Me How are coasts shaped by physical processes? You have been given a key word with a definition on it. 1. You must quiz one person to define the key term. 2. Congratulate them on a correct definition or correct their response. 3. You are then quizzed by them in the same way. 4. Swap cards 5. Move on to a new person and repeat the process VERY QUICKLY YOU WILL KNOW ALL THE PROCESSES!! 1. 2. 3. 4. What is swash? What is backwash Which of diagram below is a destructive wave? What do we call the other type of wave? What is happening on the destructive piece of coastline? What is happening on the constructive piece of coastline? The impact of geology on coastlines Rock type and structure can have a significant impact on coastal landforms. More resistant rocks such as chalk and limestone are eroded more slowly. Weaker rocks such as clays and sands are frequently weakened by heavy rainfall and marine erosion. The effect geology can have on coastal landforms can be seen on the Dorset coast. Make the shape of this coastline out of Playdough. What type of coastline is this? Discordant What type of coastline is this? Concordant Features on a Discordant coastline – Dorset 1. Erode soft rock away 2. You have made 2 bays (Studland and Swanage) 3. The hard rock left is called a headland (Ballard Point) 4. Destructive ways start to attack headlines on both sides http://www.youtube.com/watch? v=RTyOTaOsp_U 5. A crack is widened by hydraulic action and abrasion 6. Continued erosion turns a notch into a sea cave 7. Continued erosion of sea caves on either side of the headland forms an arch 8. Due to weathering and instability the arch collapses and leaves a stack 9. Continued erosion of the stack leaves a stump. 10. You have just made Old Harry Rocks Depositional features 1. Why do we get the formation of spits? 2. What is it called if a spit joins the mainland to an island e.g. Chesil Beach Dorset to the Isle of Portland? Conveyor Learning Physical reasons the coastline needs to be protected Human reasons the coastline needs to be protected Hard engineering methods Soft engineering methods 1. With the use of example explain why an area of coastline needs to be protected and the methods that are being used to protect it. (8) 2. Using a named example explain how coastal management has had an impact and the conflict it has caused. (8) Why does it need protecting? What methods are used? How has it had an impact? What conflicts have occurred? - Sheringham – Hold the Line – Rip Rap, Sea Wall, Gabions, Groynes. West Runton – Managed Retreat – old revetments – monitoring the situation Weybourne – No defences. Sheringham has kept the tourist industry and protected homes Environmentalists v. local people - - Fastest erosion rates in Europe because of the boulder clay cliffs Rising Sea Levels Economic value (towns/villages/ tourism) Agricultural land Road networks Businesses v. Planners At Weybourne they have rapid retreat which is destroying land. At West Runton the village is in increasing danger Local home owners v. tourists MARINE EROSION SUB-AERIAL PROCESSES ABRASION The wearing away of rocks by Processes active on the face and top of the cliffs the action of the sea. Waves pick up large quantities of sands and pebbles and hurl them at the face of the cliff. HYDRAULIC ACTION ATTRITION SOLUTION Waves directly break against the base of the cliffs. The sheer force of the water breaks fragments off the rock Sand particles and pebbles Sea water corrodes the cliffs are constantly colliding with and slowly dissolves chalk each other as they are moved and limestone. by the waves. WETTING AND DRYING MASS MOVEMENT LONGSHORE DRIFT Softer rocks such as clay expands and contracts as they become wet and dry. This causes weaknesses that become susceptible to erosion Movement of the cliff including rock falls, mudslides and landslides. These often occur because of a combination of waves and sub-aerial processes The transportation of material at an angle to coastline, so material travels along the coast.