plate tectonics flashcard vocabulary
Lithosphere
A lithosphere is the rigid, outermost shell of a terrestrial-type planet or natural satellite.
Asthenosphere
The asthenosphere is the highly viscous, mechanically weak, and ductile region of the upper mantle of Earth.
Mesosphere
The mesosphere is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere.
Inner Core
Earth’s inner core is the innermost geologic layer of planet Earth.
Outer Core
Earth’s outer core is a fluid layer about 2,400 km thick and composed of mostly iron and nickel that lies above Earth’s solid inner core and below its mantle.
Seismic Waves
Seismic waves are waves that travel through or over Earth.
Oceanic Crust
Oceanic crust is the uppermost layer of the oceanic portion of the tectonic plates.
Continental Crust
Continental crust, the outermost layer of Earth’s lithosphere that makes up the planet’s continents and continental shelves and is formed near subduction zones at plate boundaries between continental and oceanic tectonic plates.
Density
The density, of a substance is its mass per unit volume.
Alfred Wegener
Alfred Lothar Wegener was a German climatologist, geologist, geophysicist, meteorologist, and polar researcher.
Continental Drift
Continental drift is the hypothesis that the Earth’s continents have moved over geologic time relative to each other, thus appearing to have “drifted” across the ocean bed.
Convergent Boundary
A convergent boundary is an area on Earth where two or more lithospheric plates collide.
Divergent Boundary
A divergent boundary occurs when two tectonic plates move away from each other
Transform Boundary
Transform boundaries are places where plates slide sideways past each other.
Sea-floor Spreading
Seafloor spreading is a geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.
