Plate Tectonics Vocabulary

A slowly flowing layer of solid and melted rock formed by heat and pressure.

A

An area where two or more tectonic plates meet.

B

The area where a collision between two continental plates crunches and folds the rocks at the boundary, lifting them up and leading to mountain formation.

C

An area where two land masses on plates are pushed together and buckle and fold, creating mountain ranges.

C

An area where one plate slides under another as the two are pushed together.

C or S

Hard and rigid, the earth’s outermost and thinnest layer, only a few miles (5 km) thick under the oceans and averaging 20 miles (30 km) thick under the continents.

C

An area where contiguous plates move apart, allowing magma to rise from the earth’s interior to fill the gap.

D or S

A trembling and shaking of the earth’s surface resulting from the sudden release of energy at a transform boundary or from volcanic activity.

E

The point on Earth’s surface that is vertically above an earthquake’s focus.

E

A crack or fracture in Earth’s crust where two tectonic plates grind past each other in a horizontal direction.

F

An earthquake’s point of origin.

F

The innermost layer of the earth: an extremely hot, solid sphere of mostly iron and nickel, about 750 miles (1,200 km) thick and from 3,200-3,960 miles (5,150-6,378 km) beneath the surface.

I

Melted rock on Earth’s surface.

L

The solid outer part of Earth that includes the crust and upper mantle.

L

Melted rock beneath Earth’s surface.

M

The layer of Earth between the core and the crust, containing the lower part of the lithosphere and all of the asthenosphere.

M

A long, narrow, deep area on the ocean floor that is formed at a convergent plate boundary.

O

The liquid layer of the earth (a sea of mostly iron and nickel around 1,400 miles [2,300 km] thick) lying between the mantle and the solid inner core.

O

The name given to the supercontinent that existed more than 225 million years ago when the present-day continents were joined in a single landmass.

P

A raised area or mountain range under the oceans formed when magma fills the space between two tectonic plates that are spreading apart.

R

A dropped zone where two tectonic plates are pulling apart.

R

The process of magma oozing up from the mantle through a crack in the ocean floor, filling in the space between tectonic plates and spreading out from the plate boundary, thus creating new ocean floor and oceanic crust.

S

An area where one tectonic plate bends as it is pulled under the edge of another plate.

S

A large slab of the lithosphere that floats and moves on the asthenosphere.

T

A straight line of travel where data is being collected.

T

An area where two plates slide against each other, build up tension, then release the tension with a spurt of movement.

T

A deep valley that forms at the edge of a continent when an oceanic plate sinks underneath a continental plate.

T