4.1: Plate Tectonics

geological

concerned with geology, the science that deals with the physical nature of the earth

convergent boundary

A plate boundary where two plates move toward each other; primarily result in creation of mountain ranges, and sometimes volcanoes and earthquakes.

divergent boundary

A plate boundary where two plates move away from each other; primarily results in seafloor spreading, rift valleys, and sometimes volcanoes and earthquakes

transform boundary

A plate boundary where two plates move past each other in opposite directions; primarily results in earthquakes

earthquake

The shaking that results from tectonic plates slipping past one another. The stress of the plates pulling on each other overcomes the locked fault, releasing stored energy.

Island arcs

a curved chain of volcanic islands that form where a tectonic plate moves over a geologic hotspot

Hotspot

A weak spot in the middle of a tectonic plate where magma rises to the surface of the lithosphere; forms a volcano (ex: Hawaii & Yellowstone)

seafloor spreading

The process that creates new lithosphere on the sea floor as plates move away from each other at the mid-ocean ridges. Magma rises and cools, leading to formation of new sea floor

rift valley

A deep valley that forms where two plates move apart

tectonic plates

Large movable rock plates of lithosphere that float on top of the magma of the earth's mantle.

fault

A break in the earth's crust where there is plate movement on either side

convection currents

Circular currents in the mantle caused by the magma being heated by earth's core. Hot magma rises towards earth's surface, cools and spreads out along the lithosphere, and then sinks back down towards the core.

Mountains

Formed by two continental plates colliding and forcing each other upwards.