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, 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
a hot, dense ball of (mostly) iron.
Outer Core
liquid, iron-nickel layer of the Earth between the solid inner core and lower mantle.
Seismic Waves
waves that travel through or over Earth. may also be caused by explosions, volcanoes and landslides.
Oceanic Crust
the outermost layer of Earth’s lithosphere that is found under the oceans
Continental Crust
the relatively thick part of the earth’s crust that forms the large landmasses. generally older and more complex than the oceanic crust.
Density
the degree of compactness of a substance.
Alfred Wegener
German geophysicist who proposed the theory of continental drift.
Continental Drift
revolutionary theory explaining that continents shift position on Earth’s surface.
Convergent Boundary
When two plates come together.
Divergent Boundary
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 split apart from each other
Pangaea
a supercontinent that incorporated almost all the landmasses on Earth.
Laurasia
the more northern of two large landmasses that formed part of the Pangaea supercontinent from around 335 to 175 million years ago
Gondwana
an ancient supercontinent that broke up about 180 million years ago.
Mesosaurus
an extinct small aquatic reptile of the early Permian period, with an elongated body, flattened tail, and a long, narrow snout with numerous pointed teeth.
Glossopteris
a genus of chiefly Permian and Triassic fossil ferns or fernlike plants characterized by thick entire fronds with anastomosing veins.
