Drifting Continents
Seafloor Spreading
Theory of Plate Tectonics
Boundaries
Vocab
100
Why was Wegner's theory of continental drift rejected at his time?
He couldn't prove how the continents moved
100
What technology did scientist use to discover mid-ocean ridges? (Hint: it records the time a sound wave would bounce back and converts it into a distance)
SONAR
100
What land feature forms at a subduction zone?
Ocean Trench
100
What type of boundary is this?
Transform Plate Boundary
100
A break in the Earth's crust.
Fault
200
What force causes the movements of Earth's plates?
200
Where does subduction occur at?
Plate boundaries away from mid-ocean ridges at deep ocean trenches.
Convergent Plate Boundaries
200
What scientist was the first to map mid-ocean ridges using SONAR?
Marie Tharp
200
How do plates move at divergent boundaries?
They pull apart
200
A super continent that formed over 300 million years ago
Pangaea
300
Who was the scientist that first proposed the idea of continental drift?
Alfred Wegner
300
What process is shown in this picture?
Sea-Floor Spreading
300
How fast do tectonic plates move on average?
1-12 cm
300
How do plates move at transform boundaries?
The slip past each other
300
What is a fossil?
Any trace of an ancient organism preserved in rock.
400
What land features did Wegner use to prove that South America and Africa were once connected?
Mountain Ranges
400
What is the location called where new crust gets created?
Mid-Ocean Ridge
400
What natural phenomena occurs at the following plate boundary?
Earthquakes
400
What type of boundary is this?
How do the plates move?
Convergent Plate Boundary
They push together
400
The process of old ocean floor sinking back into the mantle.
Subduction
500
What are 3 types of evidence Wegner used to support his theory of continental drift? (NOT SEA FLOOR SPREADING)
1. Ocean Material 2. Fossils
3. Magnetic Strips 4. Nuclear Radiation
5. Glacial Deposits 6. Drilling Samples
7. Climate Evidence 8. Land Features
2. Fossils
5. Climate Evidence
8. Land Features
500
Which 3 of the following are pieces of evidence for sea-floor spreading? (NOT DRIFTING CONTINENTS)
1. Ocean Material 2. Fossils
3. Magnetic Strips 4. Nuclear Radiation
5. Glacial Deposits 6. Drilling Samples
7. Climate Change 8. Land Features
1. Ocean Material
3. Magnetic Strips
6. Drilling Samples
500
What did Marie Tharp first map on the ocean floor using SONAR?
Mid-Ocean Ridges
500
What type of boundary is this? and
Choose one of the following for what type of landform does this boundary create?
A. Volcanic Mountain Chain
B. Subduction Zone
C. Rift Valley
Divergent Plate Boundary
C. Rift Valley
500
Explain how Wegner used the evidence of fossils to help prove his theory of drifting continents.
Wegner proposed that plants like the Glossopteris and animals like the Mesosaurus and Lystrosaurus could not possibly travel the vast distance of ocean. This lead him to believe that the species lived, died and fossilized in the same location, then the landmasses moved apart. Not the species moved apart then lived, died and were fossilized in different locations.