ES + 2. Plate Tectonic Theory

Question 1

What is Seafloor Spreading Theory

Answer 1

• Occurs at Mid-Ocean Ridges: New oceanic crust forms as molten magma rises and cools at these underwater mountain ranges.
• Movement of Plates: As new crust is created, it pushes the older crust away from the ridge, causing the ocean floor to widen.
• Magnetic Evidence: The ocean floor shows patterns of magnetic reversals that create symmetrical stripes on either side of the mid-ocean ridges, indicating the history of seafloor spreading.
• Continuous Process: This process is ongoing, meaning new oceanic crust is constantly being formed while older crust is eventually recycled at subduction zones. Continually moving and regenerating from the center

Question 2

What is Continental Drift Theory

Answer 2

• Proposed by Alfred Wegener: The theory suggests that continents were once part of a single landmass (Pangaea) and have since drifted apart.
• Fossil and Geological Evidence: Similar fossils and rock formations found on different continents support the idea that they were once connected.
• Not Fully Explained: Wegener’s theory lacked a mechanism for how continents drifted, which led to skepticism until the development of plate tectonic theory.

Question 3

What is Plate Tectonics Theory

Answer 3

CDT + SST
Earth’s Lithosphere is Divided: The Earth’s crust and upper mantle are broken into large, rigid plates that float on the semi-fluid asthenosphere beneath.

Plate Movements: Caused by convection currents and driven by the molten outer core and decay of radioactive elements

Interactions Cause Geological Activity: The movement of these plates leads to earthquakes, volcanic eruptions, and the formation of mountains and ocean basins. Continually moving and regenerating from the center

Question 4

What makes CDT different from SST

Answer 4

Continental drift theory states how the earth was a large supercontinent called pangea, CDT did not provide adequate evidence on the mechanisms of plate movement howeverSS

Question 5

What makes CDT different from PTT

Answer 5

CDT did not provide the adequate evidence to explain why the plates moved.

Plate tectonics stated that the earth is made out of multiple tectonic plates that slowly move on the semi-solid asthenosphere. These movements are due to convection currents and the sea floor spreading theory. And how the they are continually moving and regenerating from the center. Alfred Wegener’s theory stated that the earth was one singular landmass and drifted apart. Lacked the mechanism of the drifting thus rejected.

Question 6

Why was CDT rejected?

Answer 6

Did not provide adequate evidence for plate movement

Question 7

1912

Answer 7

CDT Alfred Wegener

Question 8

1930

Answer 8

Convection Current Theory Authur Holmes

Question 9

1950

Answer 9

Advances in Technology, Sonary

Question 10

1960

Answer 10

SST Harry Hess