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continental drift

The hypothesis that states that the continents once formed a single landmass, broke up, and drifted to their present locations


A large "supercontinent" that is believed to have connected all of the continents on earth about 225 million years ago.

seafloor spreading

The process that creates new sea floor as plates move away from each other at the mid-ocean ridges

plate tectonics

A theory stating that the earth's surface is broken into plates that move.


Large section of Earth's oceanic or continental crust and rigid upper mantle that moves around on the asthenoshpere


rigid layer of earth made up of the crust and the upper part of the mantle


The solid, plastic layer of the mantle beneath the lithosphere; made of mantle rock that flows very slowly, which allows tectonic plates to move on top of it

convection current

Cycle of heating, rising, cooling, sinking that makes plates move.


largest layer of rock between Earth's crust and core containing the lithosphere and asthen0sphere


A boundary where plates are coming towards each other


A boundary where the plates are moving away from each other.


A boundary where the plates are sliding past each other


not completely solid or liquid; capable of being molded or changing form

oceanic crust

earth's crust located under the ocean

continental crust

The portion of the earth's crust that is less dense than oceanic crust


The process by which an oceanic tectonic plate sinks under another plate into Earth's mantle; when one plate sinks beneath another

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