plate tectonics Flashcards
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
rift valley
a long narrow valley between two diverging continental
crust
the outermost shell of a rocky planet
mantle
layer of molten rock between the crust and core
core
made up of mostly iron into the out core “molten” and inner core “solid”
tectonic plates
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 positions
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 gas or liquid rise to the top and the cooler denser parts sink
convergent boundary
when two tectonic plates come together
mountains
uplift or crustal plates that form elevated landmasses
volcanoes
a vent or fissure in the 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