Plate Tectonics

According to Wegener's hypothesis of continental drift,

• Earth's surface is made up of seven major landmasses
• the continents DO NOT move.
• Earth is slowly cooling and shrinking.
• the continents were once joined together in a single landmass and have since drifted apart

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 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 year ago.
• Wegener used several different types of evidence to support his hypothesis.
• Wegener could not identify the 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

How did scientists discover that rocks farther away from the mid ocean ridge were older than those near it?

• by observing eruptions of molten material on the sea floor
• by mapping rocks on the sea floor using sonar
• by determing the age of rock samples obtained by drilling on the sea floor
• by measuring how fast sea floor spreading occurs

Old oceanic crust is more dense than new oceanic crust because it is

• hot.
• moving toward a deep ocean trench
• cool.
• closer to the mid ocean ridge

Most geologists think that the movement of Earth's plates is caused by

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

The geological theory that states that pieces of Earth's lithosphere are in costant, slow motion is the theory of

• subduction
• plate tectonics
• deep ocean trenches
• sea floor spreading

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

• convection
• continental drift
• subduction
• conduction