Plate boundaries

• Convergent plate boundaries move toward each other/collide
• Divergent plate boundaries move away from eachother
• Transform plate boundaries slide against eachother
• What do divergent plate boundaries cause?

  • mid-ocean ridges
  • trenches
  • new rocks
  • earthquakes
• What do convergent plate boundaries cause?

  • mountains
  • volcanoes
  • subduction zones
• What do transform plate boundaries cause?

  • Earthquakes
  • Faultlines
• Wegener's initial hypothesis was that all continents used to be one big continent (Pangea) and drifted apart over time. (Continental drift)
• What was the evidence for Wegner's theory?

  • matching fossils
  • fit on coastal coastline
  • matching rocks and geological structures
• How do matching fossils support Wegner's hypothesis?

  Dinosaurs could've gotten scattered across different continents as they drifted apart
• How do fitting coastlines support Wegner's theory?

  As the continents drifted apart, they may have formed coastlines that could be put back together like a puzzle
• How do similar rocks and geological structures support Wegner's theory?

  When Pangea existed, mountain ranges formed and rocks migrated across the land, becoming split up when the continents drifted apart.
• Early-to-mid 1900s, further evidence regarding the movement of tectonic plates was discovered, thus supporting Wegner's theory.
• Why do earthquakes and volcanoes mainly form on the edges of plates?

  Volcanoes and earthquakes tend to occur most at plate edges because that's where the plates interact with each other.
• How does seafloor spreading occur?

  1. Plates diverge; move away from each other.
  2. Magma from mantle arises from into lithosphere and cools forming new rock.
  3. As plates keep moving further apart, new rock is formed, pushing old rock to the side.
  4. New sea floor is formed.