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27 Cards in this Set

  • Front
  • Back
The earth is in constant motion.

True or false.
Describe 3 motions of plate tectonics
Pushing together.
Pulling apart.
Sliding side by side.
What's a tectonic plate?
A rigid moving piece of lithosphere.
How many tectonic plates are there?
7 major
Many minor
What are the 4 types of plate boundaries?
Convergent subduction.
Convergent collision.
What are oceanic plates?
Plates mostly consists of water.

If the edges of 2 plates are oceanic.
What do oceanic plates form?
Deep ocean trenches.
What happens when oceanic plates meet continental plates?
The oceanic plate subducts.

Tsunamis, volcanic arcs, deep focus earthquakes.
What happens when 2 continental plates meet?
Neither subducts.

Forms mountains, large mountain belts, earthquakes, some volcanism
What are divergent plate boundaries?
Pulling away.

Oceanic rifts. (Valley in ocean floor)

Ridges on both sides of rift.

Weak earthquakes.
What plates meet at convergent subduction boundaries?
Oceanic plates and continental plates (where the oceanic plate subducts)

Or 2 oceanic plates (where the older ocean floor subducts)
What plates meet at convergent collision plates?
2 continental plates that don't subduct
Crust is being created and destroyed at boundaries

True or false.

Destroyed: convergent subduction boundaries

Created: divergent boundaries
Continents are stationary.

True or false.
False. Continents move over time.
Who is Abraham Ortelius?
A cartographer of the 1600s
When and who presented the idea of scientific drift?
Alfred Wegener, 1912
What is Wegener suggesting?
That the supercontinent Pangaea broke up and drifted into their current positions.
Who is Alfred Wegener?
A meterologist, a planetary scientist, suggested continental drift.
Name 4 pieces of evidence that supports continental drift
- Jigsaw fit of continents
- Fossils that fit
- Geologic structures such as mountain belts
- Ancient Climates (ice ages)
Why was Wegener's theory not accepted?
Because the theory lacked a driving mechanism.
What are 3 things they found on the ocean floor?
- Oceanic trenches
- Oceanic ridges
- Ocanic rocks that are younger than expected
Crust is continually being formed at mid-ocean ridges.

True or false?
At what rate does the sea floor spread?
2 inches per year
Why does earth behave like a bar magnet?
Earth behaves like a bar magnet due to the rotation of liquid outer core.
As basalt cools, magnetic minerals are aligned with....
North and south magnetic poles.
Where are the reversals recorded?
On the ocean floor in mirrored belts.
More evidence for Plate Tectonics
- Polar Wandering
- Earthquake Patterns
- Hotspots