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 if 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 of crustal plates that form elevated landmasses.
Volcanoes
A vent or fissure in Earth’s surface through which magma and gas are expelled.
Divergent boundary
When tectonic plates split apart.
Transform boundary
When tectonic plates slide past each other.
Fault
Break in the crust. The movement causes seismic waves which produce earthquakes.
Mid-oceanic ridge
A long ridge of underwater volcanoes between two diverging ocean plates.
Subduction zone
A plate where one tectonic plate sinks under another and melts. Also forms a trench.
