Layers of the Earth Vocabulary

Edit Answers
123456789101112131415161718
Across
  1. 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.
  2. 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
  3. 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
  4. 10. the record of the orientation of the magnetic poles with respect to the rock being studied - Remnant magnetism in ancient rocks
  5. 12. This layer of the mantle makes up the greatest volume of the earth. It is solid.
  6. 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.
  7. 16. the outermost layer of the earth which makes up the ocean floor. Thin and dense enough to be subducted.
  8. 17. This is solid iron-nickel material
  9. 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. 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.
  2. 3. Crust plus Upper mantle. This makes up the tectonic plates
  3. 4. the outermost layer of the earth. Thick crust, less dense so may not be subducted.
  4. 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.
  5. 8. Type of plate boundary where the plates slide sideways past each other. Example is the San Andreas Fault.
  6. 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.
  7. 11. the idea that new oceanic crust is created at divergent plate margins. The ocean crust and continental crust move together as a unit.
  8. 13. Solid mantle material
  9. 15. the magentic north and south poles reverse positions. Magnetic north pole coincides with geographic south pole