Continental Drift Notes

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​

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was proposed by ​

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and suggested that the ​

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are in constant motion.

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Continental drift

Alfred Wegener

continents

Harry Hess

Seafloor Spreading

oceans

Multiple Choice

Which observations led Alfred Wegener to propose the idea of continental drift?

• The continents fit together like a puzzle and fossils aligned across continents

• The continents were always stationary

• The continents were formed by volcanic activity

• The continents were separated by oceans

Multiple Choice

The presence of the same ________ on several continents supports the idea of continental drift.

• rocks
• fossils
• both fossils and rocks
• neither fossils nor rocks

Multiple Choice

Which of the following ideas supported Wegener's theory of continental drift?

• Puzzle-like fit of continents

• Fossil records

• Geologic records

• All of the above

Multiple Choice

What was the major hole in Wegener's theory that led to its rejection by the scientific community?

• He could not explain how, why, or when the continents moved

• He did not have fossil evidence

• He did not know about mid-ocean ridges

• He thought continents were stationary

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The process of

spreading was discovered using sound waves to map the ocean floor.

Multiple Choice

What is the main idea behind Harry Hess's theory of seafloor spreading?

• The ocean floor is shrinking due to earthquakes.

• Less dense, basaltic magma rises and spreads the seafloor apart.

• The continents are moving closer together.

• Mountains are formed by volcanic eruptions.

Multiple Choice

How did the Glomar Challenger's findings support both Hess's and Wegener's theories?

• By discovering new continents under the ocean.

• By finding the oldest rocks near the mid-ocean ridge.

• By showing that the youngest rocks are at the mid-ocean ridge and get older outward.

• By proving that the ocean floor never changes.

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When rocks containing iron cool, the iron aligns itself with the Earth's

poles.

Multiple Choice

Which of the following best describes the process of seafloor spreading?

• The formation of new oceanic crust at mid-ocean ridges and its outward movement on either side

• The gradual movement of continents across the earth's surface

• The remains or impression of prehistoric organisms in rock

• A theory explaining the structure of the earth's crust