Layers of the Earth Vocabulary
Across
- 2. a mechanism that helps power plate tectonics. The cooling, dense oceanic slab sinks at a subduction zone and pulls the rest of the plate with it.
- 5. Type of plate boundary where the plates move apart as magma rises to the surface from the asthenosphere.Ex: Mid-ocean ridges; mid-atlantic ridge, East Africa Rift
- 7. Type of plate boundary where plates move toward each other. One plate sinks beneath another along a subduction zone. Descending plate melts, gnerating magma. No subduction zone for two continental plates colliding. Ex: Chile and the West coast of South America, Japan
- 10. the record of the orientation of the magnetic poles with respect to the rock being studied - Remnant magnetism in ancient rocks
- 12. This layer of the mantle makes up the greatest volume of the earth. It is solid.
- 14. Middle layer of the mantle. This layer is “plastic” – the rock is soft and weak, so it is in this layer that the heat convection currents can flow. This powers plate tectonics.
- 16. the outermost layer of the earth which makes up the ocean floor. Thin and dense enough to be subducted.
- 17. This is solid iron-nickel material
- 18. a mechanism that helps power plate tectonics. The creation of new oceanic crust at divergent margins (mid-ocean ridges) pushes the plates away from each other.
Down
- 1. theory that the lithosphere is divided into rigid plates that move over the asthenosphere. Movement is on a global scale, resulting in continental drift and changing the shape, size and location of continents and ocean basins.
- 3. Crust plus Upper mantle. This makes up the tectonic plates
- 4. the outermost layer of the earth. Thick crust, less dense so may not be subducted.
- 6. the magnetic and geographic north and south poles are located at approximately the same place. This is the current day orientation of the magnetic field.
- 8. Type of plate boundary where the plates slide sideways past each other. Example is the San Andreas Fault.
- 9. An idea before plate tectonics that showed that the continents had all fit together into a giant supercontinent (Pangaea) at some point in the past. Continents had somehow moved through the oceans to their present position. Did not provide a mechanism for movement of the continents.
- 11. the idea that new oceanic crust is created at divergent plate margins. The ocean crust and continental crust move together as a unit.
- 13. Solid mantle material
- 15. the magentic north and south poles reverse positions. Magnetic north pole coincides with geographic south pole