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39 terms

Plate Tectonics Unit Terms

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Crust
The layer of rock that forms Earth's outer surface.
Oceanic Crust
The crust under the weight of the ocean.
Continental Crust
The crust that we walk on.
Lithosphere
A rigid layer made up of the uppermost part of the mantle and the crust.
Asthenosphere
The soft layer of the mantle on which the lithosphere floats.
Mantle
The layer of hot solid material between Earth's crust and core.
Inner Core
A dense sphere made up of Iron and Nickel at the center of the Earth.
Outer Core
A layer of molten Iron and Nickel that surrounds the inner core of the Earth.
Earth's Magnetic Field
Caused by the liquid outer core and makes the planet act like a giant bar magnet.
Seismic Waves
Vibrations that travel through Earth carrying the energy released during an earthquake.
Convection Currents
The movement of a fluid, caused by different temperatures, that transfers heat from one part of the fluid to another.
Divergent Boundary
A plate boundary where two plates move away from each other.
Convergent Boundary
A plate boundary where two plates move toward each other.
Transform Boundary
A plate boundary where two plates move past each other in different directions.
Divergent Ocean/Ocean Boundary
Sea Floor Spreading occurs as oceanic plates move apart at the mid-ocean ridge.
Divergent Continental/Continental Boundary
A rift valley forms where two pieces of continental crust pull apart.
Convergent Ocean/Ocean Boundary
Where two plates of oceanic crust collide, one plate is subducted beneath the other.
Convergent Ocean/Continental Boundary
The oceanic crust subducts under the continental crust.
Convergent Continental/Continental Boundary
Two continental plates collide, forming a mountain range.
Rift Valley
A deep valley that forms where two plates move apart.
Subduction Zone
The process by which oceanic crust sinks beneath a deep-ocean trench and back into the mantle at a convergent plate boundary.
Deep Ocean Trench
A deep valley along the ocean floor beneath which oceanic crust slowly sinks toward the mantle.
Mountain Range
A series of mountains that have the same general shape and structure, formed where two continental plates collide.
Island Arc
A string of Islands formed by the volcanoes along a deep-ocean trench.
Volcanic Arc
A curved chain of volcanoes formed above a subduction zone.
Mid Ocean Ridge
An undersea mountain range where new ocean floor is produced.
Fault
A break or crack in Earth's lithosphere along which the rocks move.
Basalt
A dark, dense igneous rock with a fine texture, found in oceanic crust.
Magnetic Field Reversal
When Earth's magnetic field is reversed, it can be seen as a pattern on the ocean floor at the mid ocean ridge.
Sea Floor Spreading
The process by which molten material adds new oceanic crust to the ocean floor.
Theory of Continental Drift
All the continents were once joined together in a single landmass and have since drifted apart.
Theory of Plate Tectonics
States that pieces of Earth's lithosphere are in slow, constant motion, driven by convection currents in the mantle.
Weakness for Continental Drift
Wegener could not explain what was moving the continents apart.
Evidence for Continental Drift
Wegener Found that land features, fossils, and climate change were found is different continents now thousands of miles apart.
Alfred Wegener
A scientist who came up with the hypothesis of Continental Drift, but his theory was rejected by the scientific community.
Harry Hess
Discovered mountains on the ocean floor now known as a mid ocean ridge.
Pangea
When all the continents were joined together forming a super continent.
High Risk City
A city located near a volcano or earthquake activity.
Low Risk City
A city that is not located near volcanoes or commonly receives earthquakes.