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Presentation on theme: "Https://www.youtube.com/watc h?v=ryrXAGY1dmE https://www.youtube.com/watc h?v=N9ncfAsmiSg."— Presentation transcript:

1 https://www.youtube.com/watc h?v=ryrXAGY1dmE https://www.youtube.com/watc h?v=N9ncfAsmiSg

2 Plate boundaries

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5 Why do the plates move? Convention Currents Mantle Crust

6 6 metres 36 metres928 metres200 metres The plates move at different rates. The Nazca and Pacific plates are moving apart at a rate of 18cm per year while the Eurasian and North American plates are moving apart at a rate of 3cm per year. To the nearest metre, how far will the Nazca and Pacific plates have moved over the next 200 years? How fast do plates move?

7 Constructive Plate Boundary At a constructive plate boundary, two plates move apart. As the two plates move apart, magma rises up to fill the gap. This causes volcanoes at this type of boundary. However, since the magma can escape easily at the surface the volcano does not erupt with much force. Earthquakes are also found at constructive boundaries. An example of a constructive boundary is the Mid- Atlantic Ridge.

8 Constructive plate boundary

9 Sea Floor Spreading! Did you know that the ocean floor in the Atlantic is growing by 3cm per year? Which of the following pairs of continents are moving further away from each other? 1)Europe and Africa 2)Europe and North America 3)South America and North America Mid-Atlantic ridge

10 A destructive plate boundary is found where a continental plate meets an oceanic plate. The oceanic plate descends under the continental plate because it is denser (heavier). As the plate descends it starts to melt due to the friction caused by the movement between the plates. This melted plate is now hot, liquid rock (magma). The magma rises through the gaps in the continental plate. If it reaches the surface, the liquid rock forms a volcano. Destructive Plate Boundary

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12 Collision boundaries occur when 2 plates of similar densities move together (i.e. a continental plate and a continental plate). This causes the material between them to buckle and rise up, forming fold mountains. The Himalayas are an example of a chain of fold mountains. They have been formed by the African plate colliding into the Eurasian plate. Collision Boundary

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14 Conservative plate boundaries exist where two plates do not directly collide but slide past each other along a fault (weakness). No volcanoes are found along these plate boundaries, but earthquakes do occur. An example of such a boundary is the San Andreas Fault in California. Conservative Boundary

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16 Name this plate boundary Continental crust Mantle The oceanic crust melts and rises Explosive volcanoes Oceanic plate The oceanic crust sinks under the less dense continental crust Earthquakes occur due to friction Match the labels to the letters A B C D E F G

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