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Chapter 10: Plate Tectonics
Section 3 – Theory of Plate Tectonics Study Guide
Layers of
the Earth
Plate
Movements

The outermost layer of Earth is the _________________. The crust contains much
_________________and aluminum and it is less _____________ than the next layer
beneath it.

The next layer is the _________________. The mantle is the _______________ layer, and
it is often divided into an upper part and a lower part. It is made mostly of silicon, oxygen,
magnesium, and iron.

Under the mantle lies the liquid _________________ _____________, which is made
mostly of _____________.

In the middle is the solid _____________ _____________. Pressure from the layers above
causes the inner core to be solid. The core is the __________________ layer of the Earth.

In the 1960s, scientists developed a new theory that combined _____________________
_____________ and ___________________ ____________________.

The theory of _____________ _____________________ states the Earth’s crust and part
of the upper mantle are broken into sections called _______________.
o Plates are made of the _____________ and part of the ______________
________________, together called the ____________________.

The plates move on a plastic-like layer of the _______________, an area called the
____________________.
o The rigid plates of the lithosphere _____________ and move around on the
asthenosphere like rafts.
Divergent
Plate
Boundaries
Convergent
Plate
Boundaries

When plates move, they can interact in several ways. Movement along any plate
_________________ means that ________________ must happen at other boundaries.

The boundary between two plates moving apart is called a _____________________
boundary.

________________ __________________ occurs because of divergent plate boundaries.
A mid-ocean _____________ forms where oceanic plates separate. As rising magma
cools, it forms new oceanic ________________.

_______________ ________________ occur where continental plates pull apart. The
African continent is separating now along the ___________ ________________ Rift
Valley.
As new crust is added at one location on Earth, it ________________ below the surface at
another.


Two plates move together at a __________________ boundary.

When an oceanic plate converges with a less dense continental plate, the _____________
oceanic plate _____________ under the continental plate.

The area where an oceanic plate goes down into the mantle is called a
___________________ _______________.

_____________________ form along subduction zones newly formed _______________
is forced upwards along plate boundaries.

Deep sea ___________________ form where one plate bends and sinks beneath the other
plate.

When two oceanic plates converge, ________________ _________________ form when
the colder, older, denser oceanic plate subducts below the younger oceanic plate.

When two continental plates collide, no subduction occurs. Because both of the plates are
less _____________ than the asthenosphere, the plates collide and crumple up, forming
____________________ _________________.
o ______________________ are common at these convergent boundaries.
Volcanoes do not form because there is no _______________________.
Transform
Plate
Boundaries
Causes of
Plate
Tectonics

________________ plate boundaries occur where two plates slide past one another.

The plates move in opposite __________________, or in the same direction at different
__________________.

When one plate slips past another, _______________________ occur.

The ____________ ________________ Fault in California is a ________________ plate
boundary, where the Pacific Plate is sliding past the North American Plate.

_________________ are caused by an unequal distribution of _________________.

__________, less _________________ magma rises. As it reaches near the Earth’s
surface, it _______________, becomes ______________, and _____________ back down.

The entire cycle of heating, rising, cooling, and sinking is called a ___________________
_____________________.

This process occurs in the ________________ and is the force behind ________________
___________________.

These convection currents “grab” the plates, causing plate __________________ like
convergence, subduction, and divergence.
Features
Caused by
Plate
Tectonics

_______________ forces are forces that pull apart. Tension = divergence
o Tension causes rocks to ______________. When rocks break and move along a
surface, a ____________ forms. Faults move rock layers out of ______________.
o _________________ faults form from tension. These are faults in which the rock
layers above the fault move ____________________.
o _____________ valleys and mid-ocean _______________ also form where Earth’s
crust separates.

____________________ forces squeeze objects together. Compression = convergence
o Compression forms _________________ _______________ and ______________
faults, a fault in which the rock layers above the fault surface move __________.
o At an oceanic-continental plate convergence, _______________ ranges and
___________________ can form.

At transform boundaries, _______________ - ____________ faults form. In a strike-slip
fault, rocks on opposite sides of the fault move in opposite __________________, or in the
same direction at different _________________.
o ___________________ are common along strike-slip faults.

Earthquakes, volcanoes, and mountain ranges are all evidence of ________________
_____________________. Plates move only _____________________ per year.