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the solid part of the earth consisting of the crust and outer mantle

Oceanic Crust

made of mostly basalt; about 5 - 11km thick; denser then continental crust.

Continental Crust

Made up mostly granite; about 35 km thick; less dense then oceanic crust.

Theory of Continental Drift

proposed by Alfred Wegner and Frank B. Taylor, that the continents were once joined together and have since drifted apart

Seafloor spreading

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

Subduction Zone

is an area on Earth where two tectonic plates meet and move towards one another, with one sliding underneath the other and moving down into the mantle

Divergent Plate Boundary

where two plates are moving apart, magma comes up to create new crust.

Divergent Plate Boundary

Mid-Atlantic Ridge, East Pacific Rise, Pacific-Antarctic Ridge, East African Rift are all examples of ________________

Oceanic Trench

Deep linear depression in the ocean floor where subduction is taking place.


credited with the theory of Continental Drift


credited with the theory of plate tectonics


large pieces of earths crust that move due to convection currents


large supercontinent that existed 250 million years ago

Convergent Boundary

when two plates come together

Mountain Range

formed at a continental-continental convergent boundary


outer layer of the Earth, the thinnest layer


a break in the earths crust that moves


The ocean floor is less than _________ million years old.


Discovered the inner core of the earth


plastic-like layer below the lithosphere


Proposed Seafloor spreading


This scale is used to measure the intensity of earthquakes

Radioactive Decay

The source of the majority of the heat from the inner core


Proposed Unitarianism

Hot spot

A stationary source of heat in the mantle from which a plume rises. Often result in a chain of islands such as the Hawaii islands

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