Unit 6 Vocab (25-26)

Suggests that continents are in constant motion on the surface of Earth.

The preserved remains or evidence of past living organisms.

The principle that in undisturbed rock layers, the oldest rocks are on the bottom.

The Earth’s surface is divided into large plates of rigid rocks that move with respect to each other. Each plate moves over Earth’s hot and semi-plastic mantle.

The mountain ranges in the middle of the oceans.

A long, narrow, and deep valley formed when Earth's tectonic plates move apart or pull away from each other. This causes the land in between the plates to sink down, creating a valley. Rift valleys can be found both on land and under the ocean.

The process by which new oceanic crust forms along a mid-ocean ridge and older oceanic crust moves away from the ridge.

Occurs when the Earth’s magnetic field reverses direction.

The cold and rigid outermost layer - made up of the crust and the uppermost mantle.

The layer below the lithosphere that is a hot solid that acts like a plastic material. It enables Earth’s plates to move because the hotter, plastic mantle material beneath them can flow.

The circulation of material caused by differences in density.

The boundary between two plates that move away from each other.

The land surface under the ocean.

Forms where two plates collide.

A process where the denser plate sinks below the more buoyant plate.