1. The Theory of Plate Tectonics

2. Plate Tectonics The inner structure of the Earth has different layers: is made of two layers The inner structure of the Earth has different layers: is made of two layers Core (Inner and outer)Core (Inner and outer) MantleMantle Crust (Oceanic and Continental)Crust (Oceanic and Continental)

3. The Earth’s interior 7000 C 4000 C 1000 C

4. The Lithosphere (crust and outer mantle) floats on the Asthenosphere (fluid layer). The Lithosphere (crust and outer mantle) floats on the Asthenosphere (fluid layer). The Lithosphere is broken up into tectonic plates. The Lithosphere is broken up into tectonic plates.

5. The Plates * Hover over for names

6. The plates move in relation to each other and form three different types of plate boundaries: ConvergentConvergent DivergentDivergent TransformTransform

7. How does it work? Plates move due to convection currents in the Astenosphere. The inner fluids become hotter than the outer ones. Hot fluids are less dense than cold ones, so they ascend while the colder ones descend. This makes what we call convection currents.

8. mantle convection Heat transfer from the core to the mantle produces slow convection of the mantle material (in the order of centimetres per year)

9. Mantle convection produces lateral forces at the boundary between the mantle and the crust

10. Lateral forces at the crust- mantle boundary push the crust around – in different directions – and this leads to the motion of the plates. The plates are moving at rates of cm/year

12. Kinds of Plate Boundaries

13. Convergent Occurs when plates collide. There are three types.

17. Divergent Occur when two plates are moving apart and new crust is created by magma pushing up from the Earth’s mantle.

18. Divergent Divergent boundaries create the mid-ocean ridges, where the ocean floor is created. This process is called Sea- floor spreading. As a consequence, the older rocks of the ocean floor are always closer to the continents. Divergent boundaries create the mid-ocean ridges, where the ocean floor is created. This process is called Sea- floor spreading. As a consequence, the older rocks of the ocean floor are always closer to the continents.

20. Hydrothermal vents In mid-ocean ridges, there are fractures that allow the sea water to seep down and get heated by the mantle. The hot water then forces its way back up through the crust and emerges in hydrothermal vents, or deep- sea hot springs. In mid-ocean ridges, there are fractures that allow the sea water to seep down and get heated by the mantle. The hot water then forces its way back up through the crust and emerges in hydrothermal vents, or deep- sea hot springs.

21. Hydrothermal vents The hot water coming from the mantle has sulfide minerals dissolved, that will precipitate when the water emerges from the vent and cools. These minerals form deposits, like the chimney- like black smokers. The hot water coming from the mantle has sulfide minerals dissolved, that will precipitate when the water emerges from the vent and cools. These minerals form deposits, like the chimney- like black smokers.

23. Transform Occur where plates grind past each other. As a consequence, earthquakes occur frequently in these areas.

24. Transform boundary

26. Hot Spots Hot spots are places where a plume of hot magma rises from the mantle and forces its way through the Lithosphere to form volcanoes. As the plate moves, new volcanoes are created. One example are the Hawaiian Islands. Hot spots are places where a plume of hot magma rises from the mantle and forces its way through the Lithosphere to form volcanoes. As the plate moves, new volcanoes are created. One example are the Hawaiian Islands.