Plate Tectonics & Continental Drift

According to Wegener’s hypothesis of continental drift,

• Earth’s surface is made up of seven major landmasses moving because of convection currents.
• the continents do not move.
• Earth is slowly cooling and shrinking.
• the continents were once joined together in a single landmass but have since separated.

What is Pangaea?

• the name of a German scientist
• the name of the supercontinent that existed millions of years ago
• another name for continental drift
• the name of an ancient fossil

Which of the following is the best evidence that Earth's continents were once in vastly different positions than they are today?

• Penguins are found only in the Southern Hemisphere.
• Fossils of tropical plants are found in the Arctic & Antarctica.
• Volcanoes encircle the Pacific Ocean.
• Major rivers form deltas from continental erosion.

Which type of evidence was NOT used by Alfred Wegener to support his continental drift hypothesis?

• evidence from landforms
• evidence from fossils
• evidence from human remains
• evidence from climate

Most geologists rejected Alfred Wegener’s idea of continental drift because

• they were afraid of a new idea.
• Wegener was interested in what Earth was like millions of years ago.
• Wegener used several different types of evidence to support his hypothesis.
• Wegener could not identify a force that could move the continents.

In sea-floor spreading, molten material rises from the mantle and erupts

• along the edges of all the continents.
• along mid-ocean ridges.
• in deep-ocean trenches.
• at the north and south poles.

What happens to the age of rocks as you move away from a mid-ocean ridge?

• They get younger.
• They get older.
• They increase in age then decrease in age.
• All rocks on the ocean floor are the same age.

The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle is known as what?

• convection
• continental drift
• subduction
• conduction

Most geologists today think that the movement of Earth’s plates is caused by what?

• conduction
• earthquakes
• Earth's magnetic field
• convection currents in the mantle

The diagram below shows the Mid-Atlantic Ridge. Points A through D are locations on the ocean floor. Samples of ocean-floor bedrock were collected at points A, B, C, & D. Which sequence shows the correct order of the age of the bedrock from OLDEST to YOUNGEST?

• D, C, B, A
• A, D, B, C
• C, B, D, A
• A, B, D, C