The hypothesis that the continents slowly move across earth's surface.
Continental Drift
The name of the single landmass that began to break apart 200 million years ago and gave rise to today's continents.
The preserved remains or traces of an organism that lived in the past.
An undersea mountain chain where new ocean floor is produced.
Mid ocean ridge
A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.
deep ocean trench
The process by which molten material adds new oceanic crust to the ocean floor.
sea floor spreading
The process by which oceanic crust sinks benath a deep-ocean trench and back into the mantle at a convergent plate boundary.
A section of the lithosphere that slowy moves over the asthenosphere, carrying pieces of continental and oceanic crust.
Vibrations that travel through Earth carrying the energy released during during an earthquake.
Seismic Wave
The force pushing on a surface divide by the area of that surface.
The layer of rock that forms Earth's outerskin.
Is a dark, dense, igneous rock with a fine texture, found in ocean crust.
A usually light-colored igneous rock that is found in continental crust.
Layer of hot, solid material between Earth's crust and core.
A rigid layer made up of the uppermost part of the mantle and the crust.
The soft layer of the mantle on which the lithosphere floats.
A layer of molten iron and nickel that surrounds the inner core of earth.
Outer Core
A dense sphere of solid iron and nickel at the center of Earth.
Inner Core
A plate boundary where two plates move away from each other.
Divergent Boundary
A plate boundary where two plates move toward.
Convergent Boundary
A plate boundary where two plates move past each other in opposite directions.
Transform Boundary
A break in earth's crust along which rocks move.
The theory that pieces of Earth's lithosphere are in constant motion, driven by convection currents in the mantle.
Plate Tectonics
A deep valley that forms where two plates move apart.
Rift Valley