Evidence of Plate Motions – Practice Flashcard

Front

What process helps to recycle Earth's crust by pulling old ocean floor into the mantle?

Back

Subduction at ocean trenches.

Front

Where does the new crust form as tectonic plates move apart?

Back

Mid-ocean ridges.

Front

Why is the Atlantic Ocean expanding?

Back

The Atlantic has a large mid-ocean ridge creating a new crust.

Front

What typically happens to oceanic crust as it approaches a trench?

Back

It subducts beneath another plate and returns to the mantle.

Front

Which feature is a result of subduction?

Back

Volcanic arcs.

Front

What observation helped Alfred Wegener develop his theory of continental drift?

Back

Fossilized plants and animals on different continents.

Front

How did the discovery of sea-floor spreading and subduction help explain the phenomenon of fossils of ancient plants and animals appearing on continents separated by oceans?

Back

They showed that continents were once connected and have since drifted apart.