Download The Rock Cycle

THE ROCK CYCLE
THE ROCK CYCLE IS A GROUP OF
CHANGES IN WHICH:
Igneous rock can
change into
sedimentary rock or into
metamorphic rock
Sedimentary rock can
change into
metamorphic rock or
into igneous rock.
Metamorphic rock can
change into igneous or
sedimentary rock.
IGNEOUS ROCK
Igneous rock is formed when magma cools and makes
crystals.
Magma is a hot liquid made of melted minerals. The
minerals can form crystals when they cool.
Igneous rock can form underground, where the
magma cools slowly or igneous rock can form above
ground, where the magma cools quickly.
SEDIMENTARY ROCK
Sedimentary rocks form at or near the earth's
surface at relatively low temperatures and pressures
primarily by:
deposition by water, wind or ice
precipitation from solution (may be biologically
mediated)
growth in position by organic processes (e.g.,
carbonate reefs )
METAMORPHIC ROCK
Metamorphic Rock is formed when rocky material
experiences intense heat and pressure in the crust
of the earth.
Through the metamorphic process, both igneous
rocks and sedimentary rocks can change into
metamorphic rocks, and a metamorphic rock can
change into another type of metamorphic rock.
Heat and pressure do not change the chemical
makeup of the parent rocks but they do change
the mineral structure and physical properties of
those rocks.
SEDIMENT
Sediment can either be:
Material, originally suspended in a liquid, that
settles at the bottom of the liquid when it is left
standing for a long time
Material eroded from preexisting rocks that is
transported by water, wind, or ice and
deposited elsewhere
PLUTONIC AND VOLCANIC ROCK
Volcanic rocks, or extrusive rocks or lava
rocks, crystallize when the magma
reaches the earth’s surface cooling
quickly.
Plutonic or intrusive rocks crystallize within
the crust of the earth, and as a result
plutonic rocks cool at a much slower
pace then volcanic rocks
Melting
Melting is the result of continued heating
Leads to production of magma and new igneous rocks which
are formed when the the magma cools.
This process depends on the size of the reservoir that it drains
and the relative intensity or activity of plate tectonics.
HEAT AND PRESSURE
Metamorphic rocks trapped underground are still
subject to enormous heat from rising magma, or
heated water, and pressure. Sometimes the heat
can get so intense the rocks actually melt.
Pressure comes from the incredible weight of
material surrounding the rock on all sides.
The pressure pushes new minerals into the rock and
drives other minerals out; the result, of course, is that
the rock is chemically changed.
WEATHERING
The process in which rocks are broken down by
chemical and/or physical mechanisms into smaller
particles.
There are three types of weathering
Physical weathering: physical action which breaks up
rocks. An example of this is freethaw weathering
Chemical Weathering: when the rock is attacked by
chemicals. An example of this is how acid rain breaks
down limestone.
Biological weathering: occurs when rocks are
weakened and broken down by animals and plants. A
tree root system that is slowly splitting rocks is an
example of this type of weathering..
EROSION
Erosion is the wearing away of exposed surfaces by
agents such as wind, moving water and ice. These
agents usually contain weathered rock debris. Rock
fall under gravity is also erosion.
Erosion influences orogenesis by changing the
topography and hence the thickness of the
deforming orogen, which, in turn results in
modification of the gravitational force relative to
the tectonic driving force. Whereas efficient erosion
tends to localize deformation within a relatively
narrow belt, decrease in erosional efficiency causes
deformation to propagate toward more distal sites.
Subduction
A rock that gets caught up in the subduction zone may get
dragged down with the oceanic plate.
As the rock gets dragged down, they undergo metamorphism.
Some parts of the rocks get taken all the way down to the
mantle where they slowly mix with the rest of the mantle. – this
is the only way that rocks formed on the continent get recycled
with the mantle.
COMPACTION
The result of this pressure
is a compaction of the
sediment
it is squeezed together
causing a reduction in
pore space and a
sticking together of the
grains.
Under pressure, some
chemical sediments,
like halite, may
recrystallize into a solid
state.
CEMENTATION
Most sediments are
deposited in water
containing dissolved
minerals.
The water flows through
the sediment and some
of these minerals
precipitate on the grain
surfaces.
With time, this
intergranular material
effectively glues the
sediment together into
a cohesive solid- a
sedimentary rock.
UPLIFTING
Because certain rocks are created under the
Earth’s surface A process called uplifting occurs
through orogeny and volcanic process, which
then bring rocks to the surface. The rock is
eventually becomes recycled again.
TRANSPORTATION
This process occurs when the particles created by
weathering are carried by ice, air, or water to a
region of lower energy known as a sedimentary
basin.
DECOMPOSITION
Decomposition takes place when a lowering of
hydraulic energy, organic biochemical activity, or
chemical changes occur.
CRYSTALLIZATION
When hot conditions that caused magma to melt will cool,
either because the source of heat subsides or the magma
moves into cooler regions of the Earth.
When it gets cool enough the minerals that will make up
the rock begin to crystallize and form an intergrown mass
of crystals.
If the crystals begin to form deep in the Earth where it is
relatively warm the magma cools slowly allowing the
crystals to grow relatively large.
If the magma reaches the surface, the lava cools quickly
and the crystals do not have time to grow very large.
If the crystals cannot grow at all and volcanic glass is
formed.