plate tectonics Flashcards
crust
the outermost shell of a rocky planet.
mantle
layer of molten rock between the crust and core.
core
made up iron separated into the outer core molten and inner core solid.
tectonic plate
the layer of rock that makes up the outer part of earth including the crust and upper mantle lithospheric plates.
continental drift theory
the theory continents gradually drifted over time to their present position.
asthenosphere
a thin layer of earth about 150 miles thicks at the border between the mantle and the crust.
convection current
the process in which the hotter parts of a gas or liquid rise to the top and the cooler denser parts sink.
convergent boundary
when two tectonic plates come together.
mountain
uplift of crustal plates that form elevated landmasses.
volcanoes
a vent or fissure in earths surfaces through which magma and gases are expelled.
divergent boundary
when tectonic plates split apart.
transform boundary
when tectonic plates slides past each other.
fault
break in the crust the movement cause seismic waves which produce earthquakes.
mid ocean ridge
a long ridge of underwater volcanoes between two diverging oceanic plates.
subduction zone
a place where one tectonic plate sinks under another and melts also forms a trench.
