Plate Tectonics Study Guide

1. Plate Tectonics Study Guide

2. Layers of the Earth • From the surface of the Earth the layers are the crust, mantle, outer core, and inner core.

3. Lithosphere • The Lithosphere is the Earth’s crust and the upper part of the mantle. This layer contains the tectonic plates on Earth.

4. Asthenosphere • The Asthenosphere is the layer of liquid magma in the mantle below the Lithosphere. A convection current occurs in the asthenosphere causing the Earth’s plates to move.

5. Pangaea & Continental Drift • Alfred Wegener believed that all of the continents were once connected into a super continent landmass called Pangaea. Wegener believed that over time the continents drifted apart. This theory is called Continental Drift.

6. Evidence of Continental Drift • Same fossils found on different continents • Continents fitting like puzzle pieces • Migration paths of animals • Rock structures

7. Sea Floor Spreading • The sea floor spreads at mid-ocean ridges. • Mid-oceans ridges are under water mountain chains. • Magma rises at mid-ocean ridges, solidifies, and new crust forms. • Older Crust is pushed farther away from the ridge closer to the continents. • Scientists discovered that the rocks farther away from the ridge were older because they were able to examinerock samples from drilling on the sea floor.

8. Sea Floor Spreading cont. • Here is an image of how the magma flows from the mid-ocean ridges:

9. Mid-Atlantic Ridge • This is the largest mid-ocean ridge and the longest mountain chain in the world.

10. Plate Boundaries • There are three main types: Divergent , Convergent, and Transform. Convergent Transform Divergent

11. Divergent Plate Boundary • Boundary between two plates that are moving apart • Crustal Features=mid ocean ridges at two ocean plates and rift valleys at continental plates

12. Divergent Boundary – Arabian and African Plates Plates move away from each other Arabian Plate Red Sea African Plate

13. Convergent Plate Boundaries • Boundaries between two plates that are colliding • There are 3 types of convergent plate boundary collisions: Ocean-Ocean Ocean-Continent Continent-Continent

14. Convergent Boundaries Continental-Oceanic Collisions Oceanic-Oceanic Collisions Continental-Continental Collisions

15. Subduction • Subduction is the process of a denser crust sinking beneath a less dense crust and back into the mantle. This occurs at Convergent Plate boundaries. This causes trenches and volcanoes. Active volcanoes are only located at plate boundaries.

16. Oceanic-ContinentalCollisions • Continental plate and oceanic plate collide • The denser oceanic plate sinks (subducts) beneath the less-dense continental crust • Trenches are found at this kind of plate boundary.

17. Oceanic-Oceanic Collisions • Oceanic plate collides with another oceanic plate • The denser of the 2 oceanic plates sinks (subducts) • Volcanic islands are formed at this boundary. • Trenches are found at this kind of plate boundary as well.

18. Continental-Continental Collisions • A continental plate colliding with another continental plate • This collision causes mountains ranges on the middle of continents. • The Himalayas Mnts. in Asia are an example of this kind of collision.

19. Transform Plate Boundaries • Boundary between two plates that slip past each other moving in opposite directions • Theses boundaries create faults, such as the San Andreas fault. Earthquakes form along these faults. San Andreas Fault

20. Transform Boundaries • Here is the San Andreas fault. It is an example of a transform boundary. • The Pacific plate (west of fault) is moving northwest • The North American plate (east of fault) is moving southeast Pacific Plate

21. Topographic Maps • These maps show detailed shapes of Earth’s surface. It represents different elevations specifically on mountains. • Topographic maps contain contour lines that represent the elevations. When the Contour lines are close together, it indicates a steep slope.

22. Ring of Fire • A long chain of active volcanoes and other tectonic features such as earthquakes at the plate boundaries surrounding the Pacific plate