Plate tectonics

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Lithosphere

the outer part of the earth, consisting of the crust and upper mantle, approximately 100 km thick

Convection current

current in Earth's mantle that transfers heat in Earth's interior and is the driving force for plate tectonics

Density

the mass per unit volume of a substance under specified conditions of pressure and temperature

Basalt

a hard, dense, dark volcanic rock

Magnetic field

a condition found in the region around a magnet or an electric current

Crust

outermost solid part of the earth

Mantle

the layer of the earth between the crust and the core

Upper mantle

the portion of the mantle below a depth of about 600 miles

Inner core

the central part of the earth's core

Oceanic plates 

a thick mass of igneous rock which lies under the ocean floor

Continental plates

thick continental crust

Fossil

a remnant or trace of an organism or a past geologic age

Pangea

a hypothetical supercontinent that included all the landmasses of the earth before the Triassic Period

Theory of Tectonic Plates

describes the large scale motions of earth's lithosphere

Tectonic plates

ny one of the internally rigid crustal blocks of the lithosphere which move horizontally across the earth's surface relative to one another

Continental drift

the movement, formation, or re-formation of continents described by the theory of plate tectonics

Convergent boundary

tectonic plates collide with each other

Divergent boundary

tectonic plates are moving away from each other

Transform boundary

tectonic plates are not moving directly toward or directly away from each other but rather two tectonic plates grind past each other in a horizontal direction