Plate Boundaries here you will the main plate boundaires

Plate boundaries

1. Natural Hazards: Plate Boundaries LO: To understand the main plate boundaries, how they work, their effects and the landforms that are found there.

2. PANGEA Laurasia Laurasia PANGEA PANGEA Gondwana Gondwana

3. Landforms found at Plate Boundaries Landforms Ocean Ridges Rift Valleys Deep-Sea trenches Young Fold Mountains Island Arcs Volcanoes

4. In a nutshell… Plate Boundaries There are three types: Divergent/ Constructive Convergent/ Destructive or Collisional Transform/ Conservative How can crust types affect what processes you have at convergent plate boundaries? You will get subduction if you have 1 or 2 oceanic crusts. https://www.amnh.org/explore/ology/earth/plates-on-the-move2

5. In a nutshell… Plate Boundaries There are three types: Divergent/ Constructive Convergent/ Destructive or Collisional Transform/ Conservative https://www.amnh.org/explore/ology/earth/plates-on-the-move2 Some plates are large enough to consist of both continental and oceanic crustal portions (e.g. the African or South American plates) whilst the Pacific Plate is almost entirely oceanic.

6. Constructive / Divergent This is where two plates separate or diverge from one another. When oceanic crust diverges apart from oceanic crust you get sea-floor spreading forming Mid-Ocean Ridges (Mid-Atlantic Ridge). Continental crust can stretch and spread, forming Rift Valleys (Great African Rift Valley). Rift valleys are also present on Mid-Ocean Ridges

7. Spreading Ridge What is wrong with this photo? The spreading ridge is not continuous. It is separated by transform faults . Seafloor Spreading - YouTube

8. Rift Valley

9. Rift Valley Horst Horst

10. Rift Valley

11. Rift Valley

12. Rift Valley Seafloor Spreading - YouTube

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17. Destructive ( and collisional) / Convergent This is where two plates collide or converge. There are three types of convergence, and they depend on the type of crust which converges. Oceanic Crust Vs Continental Crust Oceanic Crust Vs Oceanic Crust Continental Crust Vs Continental Crust What will happen at each boundary?

18. Destructive / Convergent

19. Destructive / Convergent

20. Destructive / Convergent Continental Vs Oceanic When oceanic crust converges with continental crust , the denser oceanic plate is subducted beneath the less dense continental crust. This process forms deep oceanic trenches. The subducted plate is melted (destroyed) in the Benioff Zone which can create magma and also cause shallow earthquakes. This magma then rises up through the asthenosphere. (Volcanoes)

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23. Destructive / Convergent Oceanic Vs Oceanic When oceanic crust converges with oceanic crust , the denser of the two oceanic plates is subducted beneath the less dense oceanic plate. This process forms deep oceanic trenches. The subducted plate is melted and forms less dense magma which rises up. Eventually this magma makes its way up into the leading edge of the overriding plate, where they punch through the crust and build volcanoes above it. The volcanoes pile up with layers until they rise above the surface of the sea/ocean. This can lead to a chain of islands

24. Destructive / Convergent Oceanic Vs Oceanic

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27. Convergent Continental Vs Continental 225 million years ago (Mya) India was a large island situated off the Australian coast separated from Asia by the Tethys Sea. When Pangea began to break up 200 Mya, India started a northward drift towards Asia at a rate of between 9 and 16 cm per year. At this time Tethys Ocean floor would have been subducting northwards, beneath Asia and the plate margin would have been a Convergent oceanic-continental one just like the Andes today.

28. Convergent Continental Vs Continental Between 40 and 20 Mya the rate of northward drift slowed as the two continental plates collided and the Tethys Ocean closed. Neither continental plate could be subducted due to their low density, causing the continental crust to thicken due to folding. The thickening of the continental crust marked the end of volcanic activity in the region as any magma moving upwards would solidify before it could reach the surface.

29. Convergent Continental Vs Continental Why is there NO subduction?

30. Convergent Continental Vs Continental http://www.youtube.com/watch?v=7gXixxYKM80

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33. Conservative / Transform Plates can move in opposite directions or in the same directions at different rates. There is no destruction of crust so therefore no volcanic activity. There are however , powerful earthquakes.

34. Plate Boundaries

35. Plate Boundaries Task: Sketch out the SEVEN plate boundaries you need to know. Label and annotate them. Ensure you include what landforms occur at these boundaries. You need not explain how they work as you have already written that down.

36. Plate Boundaries Activities : Page 223 Oxford Book :- Create a table similar to Figure 8. You need: The names of the boundaries How they work What landforms they create A named example (plates and landforms) Page 223 Oxford Book :- Complete activities 2 & 3 from the bottom of page 223 .