plate tectonics Flashcards
crust
the outermost shell of a rocky planet
mantle
layer of molten rock between the crust and core
core
made up of mostly iron separate into the outer core molten and inner core
tectonic plate
the layer of rock that makes up the outer part of the earth including the crust and upper mantle lithospheric plates
continental drift theory
the theory that continents gradually drifted over time to their present position.
asthenosphere
a thin layer of earth about 150 miles thick at the border between the mantle and the crust
convection current
the process in which the hotter parts of a glass or liquid rise to the top and the cooler denser parts sink
convergent boundary
when two tectonic plat com toghther
mountains
uplift of crustal plates that form elevated landmasses.
volcanoes
a vent or fissure in earths surface through which magma and gases are expelled
divergent boundary
when tectonic plates split apart
transform boundary
when tectonic plates slide past each other
fault
breaks in the crust the movement causes seismic waves which produce earthquakes
mid-ocean ridge
a long ridge of underwater volcanos between two diverging oceanic plates
subduction zone
a place were onne tectionic plate sinks under anthor and melts also forms a trench