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 separated into the outer core molten and inner core solid
tectonic plate
the layer of rock that makes up the outer part of the earth including the crust and upper mantle lithospheric
continental drift theory
the theory that continents gradually drifted over time to their present positions
asthenosphere
a thin layer of earth about 150 miles thik at the boreder between the mantle and the crust
convection current
the process in which the hotter parts of gas or liquid rise to the top and the cooler denser parts sink
convergent boundary
when two tectonic plates come together
mountains
uplift of crustal plates that form elevated landmasses
volcanoess
a vent or fissure on earths surface through which magma and gasses are expelled
divergent boundary
when tectonic plates split apart
transform boundary
when tectonic plates slide past each other
fault
breaks in the crust the movment cause seismic waves which products earthquakes
mid-ocean ridge
a long ridge of underwater volcanos between two diverging ocean plates
subuction zone
a place where one tectonic plate sinks under another and melts also forms a trentch