Continental Drift
Who proposed the idea of continental drift?
Alfred Wegener
What is a fossil?
Preserved remains or traces of living things.
What type of boundary is the San Andreas Fault?
Transform boundary.
A mid-ocean ridge forms at what type of boundary?
Divergent.
What is the term for large sections of Earth’s crust that move?
Tectonic plates.
What was the name of the supercontinent Wegener believed existed?
Pangaea
Similar fossils on continents separated by oceans suggest what?
The continents were once connected.
What happens at a divergent boundary?
Plates move apart.
What process creates new oceanic crust?
Sea-floor spreading.
What is subduction?
When one plate sinks under another.
Name ONE piece of land feature evidence for continental drift.
Matching mountains or rock layers on different continents.
Name one fossil that supports continental drift.
Mesosaurus or Glossopteris.
What forms when two continental plates collide?
Mountains.
What forms when one plate sinks beneath another?
A deep-sea trench.
What do we call the rigid outer layer of Earth?
Lithosphere.
Why did many scientists originally reject Wegener’s hypothesis?
He couldn’t explain how the continents moved.
How do glacial scratches in warm places support Wegener’s idea?
Those continents must have been closer to the poles in the past.
Which type of boundary creates volcanic island arcs?
Oceanic–oceanic convergent boundary.
Give one cause-and-effect relationship involving mid-ocean ridges.
Cause: Plates pull apart
Effect: New crust forms.
What is plate tectonics?
The theory that plates move and cause changes like earthquakes and volcanoes.
Explain how continental coastlines support Wegener’s theory.
Continents like South America and Africa fit together like puzzle pieces.
Tropical plant fossils in Antarctica show what about its past location?
Antarctica was once warmer and closer to the equator.
Describe the movement at a transform boundary.
Plates slide past each other horizontally.
Why is the ocean floor youngest near the mid-ocean ridge?
New crust forms there and spreads outward.
What is a rift valley?
A deep valley formed where plates diverge on land.