Continental Drift Theory

Question 1

Plate Tectonics is a synthesis of what two theories?

Answer 1

1. Continental Drift Theory by Alfred Wegener
2. Seafloor Spreading by Harry Hess and Robert Dietz

Question 2

Continental Drift Theory Maker

Answer 2

Alfred Wegener (1912), meteorologist

Question 3

Seafloor Spreading Makers

Answer 3

Harry Hess (Princeton) and Robert Dietz (Marine Coastal Geodetic)

Question 4

Types of Plate boundaries

Answer 4

1. Converging
2. Divergent
3. Transform (passive)

Question 5

Evidence 1 of Continental Drift Theory

Answer 5

Continental Fit: From Pangaea came Gondwanaland (South America and Africa) and Laurasia (North America, Europe, and Asia)

Question 6

All continents in Pangaea

Answer 6

South & North America, Africa, Eurasia, Antarctica, Australia, and India

Question 7

What is the Flaw of the Continental Drift Theory?

Answer 7

Wegener did not fully understand what causes the plates to move

Question 8

What causes the plates to move

Answer 8

The mantle’s convection currents acts like a conveyor belt and it causes the plates to slide

Question 9

What is Evidence 2 of Continental Drift Theory?

Answer 9

Distribution of Fossils

Question 10

Explanation of Distribution of Fossils

Answer 10

Fossils of (Glosopteris, Lystrosaurus, and Mezosaurus) are found in unexpected far continents

Question 11

Explain Glosopteris

Answer 11

• Fern-like plant
• seeds are too large to be airborne for long distances
• Found in Southern America Southern Africa, India, Antarctica, Australia

Question 12

Explain Lystrosaurus

Answer 12

• strictly land-dwelling reptiles
• Found in Africa Antarctica, and India

Question 13

Explain Evidence 3 of Continental Drift Theory: Match of Rock Ages and Structure

Answer 13

• Match of Mountain belts (Appalachian mountains matching with Ireland, Scotland, and Norway rocks)
• Match applicable only to rocks older than Cretaceous

Question 14

Explain Mesozaurus

Answer 14

• freshwater reptile
• found in Brazil and Africa

Question 15

Explain Evidence 4: Stratigraphy of the Continental Drift Theory

Answer 15

• similar rocks suggest similar environment of deposition

Question 16

Explain Evidence 5: Paleoclimate Indicators (CFE)

Answer 16

• Coal deposits found in Antarctica
• Fossil Coral reefs found in North America and Eurasia
• Evaporite deposits (salt)

Question 17

Explain Evidence 6: Glaciation

Answer 17

• Glacial deposits (tillites) in S.A., Afr, India, Aus.
• Glacial striations: grooves made by motion of ice - points toward the ocean (“point of origin”)

Question 18

Explain Evidence 7: Apparent Polar Wandering Curves

Answer 18

Assumption: There is always a magnetic north at any given time

Fixed Continent, Poles Wander vs. Drifting Continent, Fixed Pole

Question 19

Impacts of the Continental Theory

Answer 19

1. Continents are capable of lateral motion
2. Challenged the notion of largely up and down motion
3. Challenged the idea of permanence

Question 20

Inspiration of CDT

Answer 20

Drifting icebergs

Question 21

Why was CDT met with skepticism?

Answer 21

Wegener didn’t provide a convincing driving mechanism for the plates to move - would later be supported by Seafloor Spreading