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