Plate Tectonics/Science 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 (50 and 80 km) in altitude.
Inner Core
the innermost geologic layer of planet Earth
Outer Core
Earth’s outer core is a fluid layer about 2,260 km thick, composed of mostly iron and nickel that lies above Earth’s solid inner core and below its mantle.
Seismic Waves
an elastic wave in the earth produced by an earthquake or other means.
Oceanic Crust
the relatively thin part of the earth’s crust which underlies the ocean basins. It is geologically young compared with the continental crust and consists of basaltic rock overlain by sediments.
Continental Crust
the relatively thick part of the earth’s crust that forms the large landmasses. It is generally older and more complex than the oceanic crust.
Density
the degree of compactness of a substance.
Alfred Wegner
German climatologist
Continental Drift
the gradual movement of the continents across the earth’s surface through geological time.
Convergent Boundary
When two plates come together.
Divergent Boundary
occurs when two tectonic plates move away from each other
Transform Boundary
places where plates slide sideways past each other
Sea-floor spreading
geologic process in which tectonic plates—large slabs of Earth’s lithosphere—split apart from each other.
