The Development of Plate Tectonics

The video explores the theory of plate tectonics, starting with its basic principles and significance. It delves into Alfred Wegener's hypothesis of Pangaea and its initial rejection. The video then discusses magnetic evidence supporting plate tectonics, including studies of magnetic minerals and the discovery of magnetic striping on the seafloor. Harold Hess's contributions through ocean floor mapping and J. Tuzo Wilson's explanations of seamounts and transform faults are highlighted. The video concludes with Wilson's unified theory of plate tectonics and the concept of the Wilson cycle.

What was Alfred Wegener's major contribution to the theory of plate tectonics?

• He explained the process of subduction.

• He developed the concept of mantle plumes.

• He proposed the existence of a supercontinent called Pangaea.

• He discovered the mid-ocean ridges.

How did the study of magnetic minerals contribute to the understanding of plate tectonics?

• It helped reconstruct Earth's magnetic field over time.

• It proved the existence of Pangaea.

• It revealed the presence of underwater volcanoes.

• It showed that Earth's magnetic field is constant.

What did World War II sonar mapping reveal about the ocean floor?

• It was covered with thick layers of sediment.

• It was entirely composed of basalt.

• It contained mountain ridges, trenches, and volcanoes.

• It was a flat, featureless plain.

According to Harold Hess, what happens to oceanic crust at mid-ocean ridges?

• It sinks into the mantle.

• It is created and spreads out laterally.

• It remains stationary.

• It is destroyed by subduction.

What evidence supported Hess's theory of oceanic crust formation?

• The constant position of magnetic poles.

• The discovery of magnetic striping.

• The presence of thick sediment layers.

• The alignment of volcanic islands.

How are seamounts like the Hawaiian Islands formed according to J. Tuzo Wilson?

• Due to volcanism from stationary mantle plumes.

• By the collision of tectonic plates.

• Through the process of subduction.

• By the accumulation of sediment.

What is the role of transform faults along mid-ocean ridges?

• They create new oceanic crust.

• They connect ridge segments and accommodate spreading rate changes.

• They are sites of intense volcanic activity.

• They are responsible for the formation of seamounts.