Download The Rock Cycle

The Rock Cycle
What is the Rock Cycle?

Rock types are divided into three major groups based on how
they formed: igneous, sedimentary and metamorphic. Each
group contains a collection of rock types that differ from each
other groups on the basis of the size, shape, and
arrangement of mineral grains.

The rock cycle is an illustration that is used to explain how the
three rock types are related to each other and how Earth
processes change a rock from one type to another through
geologic time. Plate tectonic movement is responsible for the
recycling of rock materials and is the driving force of the rock
cycle.
Igneous Rock
There are places on Earth that are so
hot that rocks melt to form magma.
Because magma is liquid and usually
less dense than surrounding solid
rock, it moves upward to cooler
regions of the Earth. As the magma
loses heat, it cools and crystallizes
into an igneous rock. Magma can cool
on the Earth's surface, where it has
erupted from a volcano (extrusive
rock) or under the Earth's surface,
where it has intruded older rocks
(intrusive rock).
Basalt
Andesite
Rhyolite
Granite
Gabbro
Diorite
Metamorphic Rock

Any
rock
(igneous,
sedimentary or metamorphic)
can become a metamorphic
rock. If rocks are buried
deep in the Earth at high
temperatures and pressures,
they form new minerals and
textures all without melting.
If melting occurs, magma is
formed, starting the rock
cycle all over again.
Slate
Quartzite
Gneiss
Marble
Sedimentary Rock

Any rock (igneous, sedimentary, or
metamorphic) exposed at the Earth's
surface can become a sedimentary rock.
The forces of wind, rain, snow, and ice
combine to break down or dissolve
(weather), and carry away (transport) rocks
exposed at the surface. These particles
eventually come to rest (deposited) and
become hard rock (lithified).

Sedimentary rocks tell us what the Earth's
surface was like in the geologic past. They
can contain fossils that tell us about the
animals and plants or show the climate in an
area. Sedimentary rocks are also important
because they may contain water for
drinking or oil and gas to run our cars and
heat our homes.
Conglomerat
e
Breccia
Gypsum
Sandstone
Limestone
What type of rock do I have?
Igneous rocks are recognized by:
*
the interlocking texture of the grains
*
the presence of vesicules (holes) in extrusive igneous rocks
*
may be dark-colored and heavy
*
may display two grain sizes, one much larger than the other
Sedimentary rocks are recognized by:
*
grains cemented together
*
the presence of fossils
*
light-colored and light weight
*
may display interlocking grains but is very light weight
Metamorphic rocks are recognized by:
*
the interlocking texture of large grains
*
foliation (layering)
*
banded light and dark colors
*
"ching" sound instead of a "chunk" sound when tapped
Puu Oo, Kilauea
(1983-1986).