Plate Tectonics and Continental Drift Theory

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Questions and Answers

What concept did Harry Hess introduce in relation to oceanic geology?

Continental drift

Seafloor spreading (correct)

Magnetic field reversal

Subduction zones

What geological feature is primarily associated with the creation of new ocean crust?

Ocean trenches

Mid-ocean ridges (correct)

Island arcs

Continental shelves

What significant evidence supports the theory of seafloor spreading?

Glacial deposits in tropical areas

Fossil records from volcanic islands

Presence of limestone on continental shelves

Magnetic striping of ocean floor rocks (correct)

During which historical event was significant mapping of the ocean floor conducted?

World War II Signup and view all the answers

What occurs at mid-ocean ridges according to the seafloor spreading theory?

Molten material erupts and spreads Signup and view all the answers

What type of rocks indicate that molten material has erupted from mid-ocean ridges?

Rock pillows Signup and view all the answers

What role do trenches play in the seafloor spreading process?

Trenches are zones where ocean crust is destroyed. Signup and view all the answers

What was a consequence of Harry Hess's mapping work during the international Indian Ocean Expedition?

Development of the theory of plate tectonics Signup and view all the answers

What feature makes up the tectonic plates?

Rigid lithosphere Signup and view all the answers

What was the hypothesis proposed by Alfred Wegener?

Continents were once joined as a supercontinent. Signup and view all the answers

Which ocean surrounded the supercontinent Pangaea?

Panthalassa Signup and view all the answers

What is the primary reason the theory of continental drift was initially rejected?

The lack of a strong force for movement. Signup and view all the answers

What does the term 'tectonic' refer to in relation to plate tectonics?

Deformation of the crust Signup and view all the answers

What characterizes the lithosphere?

It is a combination of the crust and upper mantle. Signup and view all the answers

Which of the following was a significant factor in the rejection of the continental drift theory?

Geographical bias in scientific communities. Signup and view all the answers

What type of geological structure is formed from the interaction of tectonic plates?

Volcanoes Signup and view all the answers

What type of boundary occurs when two tectonic plates move towards one another?

Convergent Boundary Signup and view all the answers

Which of the following best describes oceanic drilling samples found at ocean ridges?

Younger rocks are found in the center of the ridge. Signup and view all the answers

What is the average rate of tectonic plate movement for most regions?

Approximately 0.60 cm to 10 cm per year Signup and view all the answers

What movement characterizes transform boundaries?

Plates slide past each other horizontally. Signup and view all the answers

Which type of convergent boundary involves oceanic crust colliding with continental crust?

Ocean-Continent boundary Signup and view all the answers

Which of the following is NOT a type of convergent boundary?

Divergent Signup and view all the answers

Which ocean has the fastest average rate of tectonic plate movement?

Pacific Ocean Signup and view all the answers

In which type of convergent boundary do two continental plates collide?

Continent-Continent Signup and view all the answers

Study Notes

Plate Tectonics

Earth's crust is divided into 7 major plates that move.
Plate movement causes collisions, separations, or friction.
Interactions create Earth structures (tectonic features).
Tectonic refers to crust deformation due to plate interaction.
Lithosphere comprises crust and upper mantle.
Asthenosphere underlies lithosphere.
Plates move due to underlying mantle convection cells.

Continental Drift Theory

Proposed by Alfred Wegener.
Continents were once assembled into one supercontinent (Pangaea).
Continents drifted apart over geologic time, now spread across the globe..
Evidence includes continental shapes fitting together, fossil distribution, and glacial deposits.

Rejection of Continental Drift Theory

Many influential scientists were in the Northern Hemisphere, with data mostly from the Southern Hemisphere.
Plausible alternative explanations for fossil and glacial distributions existed.

Seafloor Spreading

Proposed by Harry Hess (1962).
Ocean floors act like conveyer belts, shifting continents.
New crust is formed at mid-ocean ridges.
Older crust is destroyed at ocean trenches.
Molten material from the mantle rises and erupts at mid-ocean ridges.
Evidence includes the mountain ranges of mid-ocean ridges, and rock formations that were the result of lava flow and cooling.
Newly formed rocks show magnetic reversals.

Types of Plate Movement

Convergent: Plates collide.
- Ocean-continent: Oceanic crust dives below continental crust.
- Ocean-ocean: One oceanic plate dives below another.
- Continent-continent: Two continental plates collide.
Divergent: Plates move apart.
Lateral/Transform: Plates slide past each other.
Plate movement rate varies (0.60 cm/yr to 10 cm/yr).
Research suggests average rate is around 0.6-10 cm per year.

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Description

Explore the fascinating concepts of plate tectonics and continental drift. This quiz covers the movement of Earth's plates, the evidence for Alfred Wegener's theory, and the rejection of this theory during its time. Test your knowledge on how these geological processes shape our planet's structure.