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 mostley iron. separated in 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 plates)
continental drift theory
the theory that continents gradually drifted over time to teir present positions
asththenosphere
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 gas or liquid rise to the top and the cooler denser parts sink.
convergant boundray
when two tectonic plates come together.
mountains
uplift of crustal plates that form elevated land masses.
volcanoes
a vent or fissure in earths surface through wich magma and gasses are expelled
divergent boundray
when tetonic plates split apart
transform boundary
when tectonic plates slide past each other.
fault
breaks in the crust the movement causes seismic dwaves which produces earthquakes.
mid-ocean ridge
a long ridge of underwater volcanoes between two divergingmoceanic plates
subduction zone
a place where one tectonic plate sinks under another and melts also forms a trench