The preserved remains of ancient organisms.

An undersea mountain chain where new ocean floor is produced; a constructive (divergent) plate boundary.

The theory that links together the ideas of continental drift and ocean-floor spreading and explains how the Earth has changed over time.

A V-shaped valley on the ocean floor where old ocean floor is subducted; a destructive (convergent) plate boundary.

A plate boundary at which plates come together.

German Scientist who came up with the theory of continental drift.

The process I which old ocean floor is pushed away from a midocean ridge by the formation of new ocean floor.

The branch of geology that deals with the movements that shape the Earth's crust.

The process in which crust plunges back into the interior of the Earth.

A plate boundary at which two plates slip past one another horizontally.

The single giant landmass that existed more than 200 million years ago and gave rise to the present-day continents

A fault that runs across a midocean ridge.

There are _________ major lithospheric plates.

The topmost solid part of the Earth, which is composed of the crust and some of the mantle.

A movement of material caused by differences in temperature.

The theory that the continents were once joined together and have since drifted apart.

Scientists discovered that the history of the Earth's magnetism is recorded in _______________?

There are __________ types of plate boundaries.

In plate tectonics, one of the moving, irregularly shaped slabs that make up the Earth's lithosphere.

The largest lithospheric plate is the _________?

These fossils are found in rocks 250 million years old and have been found in South Africa, Australia, India, and Antarctica, and they have seeds.

During the past 3.5 million years, the Earth's magnetic poles have reversed themselves __________ times.

When two oceanic plates collide the _________ plate is subducted under the younger plate.

A plate boundary at which plates move apart.

The San Andreas Fault is an example of a __________ boundary.