Plate Tectonics Vocab - Holland

Seismic Wave

Vibrations that travel through the Earth carrying the energy released during an earthquake

Transform Boundary

A plate boundary where two plates move PAST each other in opposite directions.

Convergent Boundary

A plate boundary where two plates move TOWARD each other.

Divergent Boundary

A plate boundary where two plates move AWAY from each other.

Inner Core

A dense sphere of SOLID iron and nickel at the center of the Earth.

Outer Core

A layer of molten (LIQUID) iron and nickel that surrounds the inner core of the Earth.

Theory of Plate Tectonics

The theory that pieces of Earth's lithosphere are in constant motion driven by the convection currents in the mantle.

Asthenosphere

The soft layer of the mantle on which the lithosphere floats.

Lithosphere

A rigid layer made up of the uppermost part of the mantle and the crust.

Fault

A break in the Earth's crust where masses of rock slip past each other.

Crust

The layer of rock that forms Earth's outer surface.

Mantle

Layer of hot, solid material between Earth's crust and core.

Rift Valley

A deep valley created when two continental plates move apart.

Trench/Deep Ocean Trench

A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.

Plate

A section of lithosphere that carries pieces of continental and oceanic crust.

Convection Currents

The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another.

Oceanic Crust

The Earth's crust that lays beneath the ocean. It consists mainly of rocks such as basalt.

Continental Crust

The Earth's crust that forms the continents. It consists mainly of rocks such as granite.

Subduction

The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.

Sea-Floor Spreading

The process by which molten material adds new oceanic crust to the ocean floor.

Pangaea

The name of the single land mass that broke apart 200-300 million years ago and gave rise to today's continents.