Unit 9/Plate Tectonics and Topographic Maps

constructive force
a force that builds up mountains and landmasses on Earth's surface
continental drift
the gradual movement of the continents across the earth's surface through geological time.
contour line
a line on a topographic map that connects points of equal elevation
convergent boundary
A plate boundary where two plates move toward each other
the thin and solid outermost layer of the Earth above the mantle
destructive force
any natural process that tears down or wears away Earth's surface
divergent boundary
A plate boundary where two plates move away from each other
the height of land above sea level
condition in which the earth's surface is worn away by the action of water and wind
a break in a body of rock along which one block slides relative to another
anything that happened in the past
A rigid layer made up of the uppermost part of the mantle and the crust.
mid-ocean ridge
An undersea mountain chain where new ocean floor is produced.
plate tectonic theory
The scientific theory that the surface of the Earth is broken up into plates that are in constant motion
Ancient landmass made up of all the continents that began to break apart about 200 million years ago.
Sections of the Earth's crust that move due to convection currents.
rift valley
long, narrow depression that forms when continental crust begins to separate at a divergent boundary
seafloor spreading
The process that creates new sea floor as plates move away from each other at the mid-ocean ridges
process by which one tectonic plate slips beneath another tectonic plate
transform boundary
A plate boundary where two plates move past each other in opposite directions
extremely deep areas in the ocean that are created by a subducting plate

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