Plate Tectonics Flashcards
the single huge continent that existed 245 million years ago.
Pangaea
the process in which a denser tectonic plate is pushed downward beneath a less dense plate when plates converge
subduction
the soft upper layer of the mantle just below the lithosphere.
asthenosphere
cool, rigid, outermost layer of Earth that is divided into enormous pieces called tectonic plates
lithosphere
a large valley shaped area of the earth in which plates of the earth’s crust are moving away from each other
rift valley
deep and narrow depressions in the seafloor where the subducted plate moves into the asthenosphere
oceanic trench
underwater mountain ranges where crust is spreading apart creating new ocean floor
oceanic ridge
crack within Earth’s crust where rock has been fractured and where rocks move past each other
fault
the boundary between two tectonic plates that slide past one another
transform boundary
the boundary between two tectonic plates moving away from each other
divergent boundary
the boundary between two tectonic plates moving toward each other
convergent boundary
occur where the edges of tectonic plates meet
plate boundary
a cyclical motion occurs because of density differences in a fluid that happens in the asthenosphere
convection currents
process by which new oceanic lithosphere forms at mid-ocean ridges as tectonic plates are pulled away from each other
sea floor spreading
the theory that continents were once connected, but have drifted apart.
continental drift theory
