Download Rock Cycle


Weathering wears rocks at the Earth’s surface down into smaller pieces. The two
types of weathering are:

Physical (Mechanical) Weathering: occurs when fragments of rock break off due
to wind, changing temperature, tree growth, or water freezing inside cracks in
the rock.

Chemical Weathering: occurs when minerals in rock are dissolved or otherwise
chemically changed by acidic water (hydrolysis) or rusting (oxidation).
http://www.brainpop.com/science/weather/weathering/
The small fragments produced by weathering are called
sediment. This includes broken pieces of rock, sand,
silt, clay and chemical precipitates (the solid materials
left behind after a liquid evaporates).
• Erosion occurs when these sediments are removed
from rock by running water, ice, or gravity.
• During sedimentation, which is also known as
deposition, the sediments are laid down or
deposited, and remain where they lay unless moved
by some other agent of erosion.
http://www.brainpop.com/science/earthsystem/erosion/

Rock Cycle-Continuous
changing and
remaking of rocks.
 Any of the 3 types of
rocks can be
transformed into
another type of rock by
natural Earth processes.
 http://www.brainpop.com/scienc
e/earthsystem/rockcycle/
 https://www.youtube.com/watch
?v=pm6cCg_Do6k

Igneous rock is formed from the crystallization
(cooling and hardening) of magma.
 Granite-Makes up Earth’s continental crust.
 Basalt-Makes up Earth’s oceanic crust.

Igneous rock can form in many different
environments.

The chemical composition of the magma and the
rate at which it cools will determine what type of
igneous rock forms.

Igneous rocks can cool slowly beneath the surface
or rapidly above the surface.

As the magma cools, the rate of cooling will
determine how much time the crystals have
to form.

Slow cooling produces larger crystals, while
fast cooling produces smaller crystals.

The size of the crystals that make up a rock
are used to help classify the rock.

Sedimentary rock forms from the
compaction and cementing together of
sediments after deposition.
 Examples include sandstone and
limestone.

Bedding is the horizontal layering of
sedimentary rocks.

Bedding can occur in very thin layers
or in very thick layers, and be graded
or criss-crossed.
Graded Bedding
Cross-bedding

Imagine you are apart of a parent rock and
suddenly you find yourself weathered and are
now a piece of sediment. I want you to write
at least ½ of a page describing your journey.
 What did you see?
 Why did you get weathered?
 What is causing you to erode?
 Where do you end up?
 What are some interesting things you saw on your
journey?
Metamorphic rock forms when igneous or sedimentary
rocks are changed by heat and/or pressure below Earth’s
surface.
 The heat allows atoms to rearrange themselves.

 Examples are gneiss and marble.

When a rock is exposed to extreme heat and
pressure within the Earth but does not melt, the
rock becomes metamorphosed.

Metamorphism may change the mineral
composition and/or the texture of the rock.

Metamorphic rock is classified into two groups.

Foliated: having long wavy layers of crystal that
are perpendicular to the pressure that formed the
rock.

Non-Foliated: having blocky crystal shapes that do
not line up in any one direction under the pressure
that formed the rock.
Foliated Gneiss
Non-foliated Marble

Igneous Rock
Formation:
Sedimentary and
metamorphic rock can
be melted down, and
then cooled to form
igneous rock.

Sedimentary Rock Formation:
Igneous or metamorphic rocks can become weathered
and eroded and then lithified (compacted and cemented)
into sedimentary rocks.

Metamorphic Rock
Formation:
Igneous and
sedimentary rock can
be transformed by heat
or pressure to form
metamorphic rock.
http://www.bbc.co.uk/bitesize/ks3/science/environment_earth
_universe/rock_cycle/activity/
• The rock cycle demonstrates
the relationships among the
three major rock groups.
• It is powered by the interior
heat of the Earth as well as
earth’s momentum and the
energy from the sun.
• It involves processes on the
Earth’s surface as well as
the Earth’s interior.
• It connects the “hydrologic
cycle” with the “tectonic
cycle”.
Summary
• The three main rock types are igneous,
metamorphic and sedimentary.
• The three processes that change one rock to
another are crystallization, metamorphism,
and erosion and sedimentation.
• Any rock can transform into any other rock
by passing through one or more of these
processes. This creates the rock cycle.
http://www.phschool.com/atschool/phsciexp/active_art/rock_cycle/index.html