Download The Rock Cycle

The Rock Cycle
The Rock Cycle

The Rock Cycle shows how three basic rock
types form Igneous, Sedimentary,
Metamorphic, and illustrates how geologic
processes transform one rock type into
another.
The Rock Cycle
Igneous Rocks

Igneous Rocks originate when molten material called
magma, cools and solidifies.

This process, called crystallization may occur either at
the Earth’s Surface or beneath the Earth’s Surface.

When igneous rocks are exposed at the surface, they
will undergo weathering, a process which slowly breaks
down rock.

The rock fragments are picked up and transported by
agents of erosion such as running water, glaciers, wind,
rain.
Erosion: the incorporation and transportation of material
by a mobile agent, such as water, wind, or ice.
The Rock Cycle
Sedimentary Rock

Eventually, these particles and dissolved substances,
called sediment, are deposited.

Next, the sediments undergo a process called
lithification, meaning “conversion to rock” either by
compaction or by cementation as percolating water
coats the sediment with mineral matter and gradually
cement the particles together.

The result is sedimentary rock such as:
sandstone

conglomerate
shale
If sedimentary rock is buried deep within Earth or
involved in the dynamics of mountain building, it will be
subjected to great pressures and heat.
The Rock Cycle
Metamorphic Rock

Rocks subjected to great pressure and high
heat change into metamorphic rocks.

When rocks in a high temperature
metamorphic environment are subjected to
directional forces, they are easily
transformed.

When metamorphic rock is subjects to still
greater heat and/or pressure changes, it
may melt to create magma!
The Rock Cycle

As we have seen, rocks are
transformed from one type
of rock to another in an
unending cycle we call the
rock cycle.

Earth’s materials do not
always follow the paths
shown in the rock cycle
diagram. It is just as likely
that other paths will be
followed.

Although rocks may seem to
be unchanging masses, the
rock cycle shows that they
are NOT.

The changes, however, take
time – sometimes millions
or even billions of years.