Plate tectonics and magnetic reversal (4.3)

Theory of Plate Tectonics

theory that explains how large pieces of the Earth's outermost layer move and change shape

tectonic boundary

where tectonic plates touch

pushed

At a convergent boundary plates are ______, depends on which type of plates are converging.

plates sea floor mid-ocean ridge volcanic

At a divergent boundary ____ move apart, ____ spreads, _____, and ____ activity.

laterally earthquakes

At a transform boundary plates move ____ past eachother and many ____.

collide deform thickens mountains

At continental/continental convergent boundaries both plates ____ and ____. The crust ____ as ____ are pushed upward.

older trench island arc rising magma

At oceanic/ oceanic convergent boundaries the ____ oceanic plate will sink beneath the other and a ____ is created in between the plates, an ____ is created due to ____.

oceanic crust denser continental crust trench subduction zone mountain range continental crust

At oceanic/continental convergent boundaries the ____ sinks, subducts, because it is ____ than ____. A ____ forms at the _____. _____ forms on the _____.

cools more dense sink

When rock ____, it becomes ____, and tends to ____.

heated less dense rise

When rock is _____, it becomes ____ and tends to _____ to the surface of the Earth.

Sea- floor spreading

____ takes place at a rift.

transform boundary earthquakes

_____ causes strike-slip faults and produces _____.

ridge

-build up of magma on either side of the rift

magnetic reversal

-change in the Earth's magnetic field resulting in the magnetic north being aligned with the geographic south, and the magnetic south being aligned with the geographic north.

rift

-crack, where magma rises

definition of sea-floor spreading

-the process by which new oceanic lithosphere forms as magma rises toward the surface and solidifies

oceanic/oceanic oceanic/continental

Convergent subduction occurs at ____ and ____.

thermal energy

Density changes in the asthenosphere are caused by the flow of ____ from deep within the Earth.

hot iron core

Earth's magnetic field is generated by the ____.

tectonic plates

Earth's outermost layer is called ____.

very slowly GPS Global Positioning System

Tectonic plates move ____, their speed is measured by ____ (____).

convergent boundary

boundary formed when tectonic plates collide

divergent boundary

boundary formed when tectonic plates separate

transform boundary

boundary formed when tectonic plates slide past horizontally