Plate Tectonics Flashcards
Lithosphere
outermost rigid layer of the earth
Asthenosphere
a plastic layer of the mantle on which the lithosphere moves
Mesosphere
strong, lower part of the mantle
Outer Core
liquid layer that lies beneath the mantle and surrounds the inner core
Inner Core
solid, dense center of the earth that is mostly iron
Seismic Waves
an elastic wave in the earth produced by an earthquake or other means
Oceanic Crust
the thin part of the earth’s crust that underlies the ocean basins
Continental Crust
the thick part of the earth’s crust that forms the large landmasses
Density
the mass of a substance per volume unit
Alfred Wegener
German geophysicist who proposed the theory of continental drift
Continental Drift
the gradual movement of the continents across the earth’s surface through geological time
Convergent Boundary
a tectonic boundary where two plates are moving toward each other
Divergent Boundary
a tectonic boundary where two plates are moving away from each other and new crust is forming from magma that rises to the Earth’s surface between the two plates
Transform Boundary
where the two plates slide against each other in a sideways motion
Sea-floor Spreading
the formation of new areas of oceanic crust
