Continental Drift & Sea-Floor Spreading

The process by which the ocean floor sinks beneath a deep-ocean trench and back into the mantle again.

Scientists use ________, which uses sound waves to measure the distance to an object.

In 1910, a scientist named __________ was curious about why some continents look like they could fit together.

Seams that form mountain ranges that run along the middle of ocean floors.

Continents were joined together in a supercontinent, about _________ years ago.

The mid-ocean ridges form the _______ mountain ranges on Earth.

Because Wegener could not identify the cause of continental drift, most geologists _______ his idea.

The process in which mid-ocean ridges continually add new material to the ocean floor.

During sea-floor spreading, lava cools into new ocean floor and the older ocean floor gets pushed __________.

The mesosaurus fossils found in South America and Africa are which type of evidence?

The continents are no longer drifting.

During subduction, the ocean floor plunges into deep underwater canyons. These canyons are called __________ .

Which was NOT used by Wegener as evidence of continental drift?

With sonar, scientists found that mid-ocean ridges extend into all of Earth’s _________.

Wegener’s idea that the continents slowly moved over Earth’s surface.

Wegener called the supercontinent _____________.

Folded moutains in South America and Africa are which type of evidence?

What substance emerges up through a mid-ocean ridge?

According to Wegener, the continents were joined together in a(n) _____________.

Any trace of an ancient organism that has been preserved in rock.