plate tectonics Flashcards
Lithosphere
the rigid outer part of the earth, consisting of the crust and upper mantle.
Asthenosphere
the upper layer of the earth’s mantle, below the lithosphere, in which there is relatively low resistance to plastic flow and convection is thought to occur.
Mesosphere
the region of the earth’s atmosphere above the stratosphere and below the thermosphere, between about 30 and 50 miles in altitude
Inner Core
Earth’s innermost part and according to seismological studies
Outer Core
a liquid layer about 2,300 km thick and composed of iron and nickel that lies above Earth’s solid inner core and below its mantle
Seismic Waves
waves of energy that travel through the Earth’s layers, and are a result of an earthquake, explosion, or a volcano that gives out low-frequency acoustic energy
Oceanic Crust
the relatively thin part of the earth’s crust that underlies the ocean basins
Continental Crust
the layer of igneous, sedimentary, and metamorphic rocks that forms the continents and the areas of shallow seabed close to their shores, known as continental shelves.
Density
a characteristic property of a substance
Wegener
a German polar researcher, geophysicist and meteorologist
Continental Drift
the movement of the Earth’s continents relative to each other, thus appearing to “drift” across the ocean bed
Convergent Boundary
an actively deforming region where two or more tectonic plates or fragments of the lithosphere move toward one another and collide.
Divergent Boundary
a linear feature that exists between two tectonic plates that are moving away from each other.
Transform Boundary
a strike-slip fault that offsets a mid-ocean ridge in opposing directions on either side of an axis of seafloor spreading.
Sea-floor Spreading
a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge
