Transcript The Rock Cycle

The Rock Cycle
The Rock Cycle is
a group of
changes in
which:
Each type of
rock can change
into each of the
other types.
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 (intrusive) or above ground, where the lava
cools quickly (extrusive).
Plutonic and Volcanic Rock
Extrusive rocks or lava rocks, crystallize when the
magma reaches the earth’s surface cooling
quickly. (no time for crystals to form, crystals are
very small)
Intrusive rocks or plutonic rocks crystallize within
the crust of the earth, so intrusive rocks cool at a
much slower pace than extrusive rocks (longer
time for crystals to form, crystals are bigger)
Melting
Melting is the result of continued heating
Leads to production of magma and new igneous rocks which
are formed when the magma or lava cools.
Metamorphic Rock
Metamorphic Rock is formed when rocky material
experiences intense heat and pressure in the crust
of the earth.
Through the metamorphic process, igneous rocks,
sedimentary rocks and metamorphic rocks can
change into metamorphic rocks,
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.
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.
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 (ex. sediment
settling after being suspended in water)
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
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.
This “cements” the grain
surfaces together
Compaction
Sediment is compacted
together
Example: Sandstone
What might get stuck in
sedimentary rock as it forms?
Nearly all the fossils that have
been found to date have been
found in Sedimentary rock.
As organisms die they settle
into the layers of the sediment
and become buried.
Weathering
The process in which rocks are broken down by chemical
and/or physical mechanisms into smaller particles.
There are two types of weathering
Mechanical weathering: physical action which breaks
up rocks.
Example: Freezing and melting of water
This includes Biological weathering which occurs when rocks are
weakened and broken down by animals and plants.
Example: A tree root system that is slowly splitting rocks is an
example of this type of weathering..
Chemical Weathering: when the rock is attacked by
chemicals.
Example: acid rain breaks down limestone.
Erosion
Erosion is the removal or transportation of
material by wind, water, or ice.