Lithosphere

Lithosphere

The rigid outer layer of the Earth, consisting of the crust and upper mantle.

Plate tectonics

The theory that describes the movement of large plates that make up the Earth's lithosphere.

Continental shelf

The shallow ocean area surrounding the edges of continents.

Seamounts

Underwater volcanoes that do not reach the ocean surface.

Volcanic islands

Islands formed when volcanoes grow all the way up from the ocean floor to the surface.

Trenches

Deep depressions in the ocean floor formed where two tectonic plates move toward each other.

Ridges

Elevated areas on the ocean floor formed where tectonic plates move apart and molten rock rises.

Mountain ranges

Elevated landforms that influence the direction of drainage and where water flows.

Glaciers

Large moving bodies of ice that flow and change the landscape.

Continental glaciers

Glaciers that cover large areas of land.

Valley glaciers

Glaciers that move through mountain valleys and carry rocks of different sizes.

Moraines

Piles of rocks and gravel deposited by glaciers.

Eskers

Ridges of sand and gravel formed by glacial meltwater.

Drumlins

Small teardrop-shaped hills formed by glacial movement.

Colder climate

Conditions that cause glaciers to grow and advance forward.

Warmer climate

Conditions that cause glaciers to melt and retreat.