4.1 Evidence of Plate Motions

Front

What is the evidence that rocks farther away from the mid-ocean ridge are older?

Back

Scientists determine the age of rock samples obtained by drilling on the sea floor.

Front

What drives the movement of tectonic plates?

Back

Mantle convection currents.

Front

What prevents Earth from continuously growing due to new land from mid-ocean ridges?

Back

Subduction areas and trenches.

Front

What type of evidence supports the theory of Continental Drift related to the giant fern Glossopteris?

Back

Fossil/climate evidence.

Front

What was the name of the single landmass that began to break apart 200 million years ago?

Back

Pangaea.

Front

What are mid-ocean ridges?

Back

Underwater mountain ranges formed by plate tectonics.

Front

What is subduction?

Back

The process where one tectonic plate moves under another and sinks into the mantle.

Front

What is the theory of Continental Drift?

Back

The hypothesis that continents have moved over geological time and were once joined together.

Front

What is sonar used for in oceanography?

Back

To map the sea floor and study underwater features.

Front

What is the significance of trenches in plate tectonics?

Back

They are areas where subduction occurs, leading to recycling of the Earth's crust.