BY
Basic processes
and major rocks types:
- Metamorphic
- Sedimentary
- Igneous
visual.ly/rock-cycle
Rock cycle - an idealized cycle of processes undergone by rocks
What drives the rock cycle?
Any type of rock can change
(igneous and metamorphic rocks)
External processes powered by
energy from the Sun
(sedimentary rocks)
Earth’s internal heat
- subduction melting
and metamorphism
(References:)
- geolsoc.org.uk
- scienceblogs.com
- lauracrandler.com
- rgsenergy.com
- weathering, erosion
and deposition
- Sun moves the wind
and water at the surface
with enough force to
break rocks apart into
sand and other types of
sediment
Metamorphosis (to change form)
Metamorphic Rocks
Process: intense heat and pressure
Pressure
500 bars – 1200 bars
Heat
200°C - 850°C
Why
(References:)
- learner.org
- mineralogy4kids.org
- 1.bp.blogspot.com
- upload.wikimedia.org
is it important?
- aids in the interpretation of the plate
tectonic setting in which the metamorphism
took place
- reconstruction of the geological history
How
does it happen?
- temperature and pressure conditions (metamorphic
environment) in which the rock was formed
- composition of the original unmetamorphosed, rock
This process happens
under the surface of
the Earth
Characteristics (ribbonlike layers, crystals)
Metamorphic Rocks
Examples (phyllite and marble)
(Gneiss)
(References:)
- sacgeologymuseum.files.wordpress.com/2013/09/gneiss.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/anthracite-coal.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/phyllite-luster-andmini-undulations.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/marble2.jpg
- learner.org
Phyllite
Intense heat and
pressure results in
ribbon like layers
Before, phyllite was
slate (also a
metamorphic rock)
Marble
(Anthracite Coal)
Shiny crystals,
formed by minerals
Marble used to be
limestone (a
sedimentary rock)
(References:)
- cdn.shopify.com
- getfillings.com
- learner.org
- mineralogy4kids.org
Sedimentation (to settle)
Sedimentary Rocks
Process: weathering, erosion, deposition, lithification
(Schleie)
Why
is it important?
- tell us what Earth's surface was like in the
geologic past, can contain fossils about the
animals, plants or show the climate in an area
- because they may contain water for drinking
or oil and gas to run our cars and heat our
homes
How
does it happen?
- forces of wind, rain, snow, and ice combine to break
down and carry away rocks exposed at the surface.
- particles eventually come to rest and become hard
rock
Characteristics (fairly soft, layers of sediment)
Sedimentary Rocks
Examples (conglomerate and sandstone)
(Quartz Sandstone)
(References:)
- sacgeologymuseum.files.wordpress.com/2013/09/quartz-sandstonebeach.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/chert.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/conglomerate.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/arkose.jpg
- learner.org
Conglomerate
Generally, fairly soft
may break apart or
crumble easily
composed of
rounded gravel,
pebbles, cobbles, or
boulders along with
smaller rock pieces.
Sandstone (Arkose)
(Chert)
Sediment
accumulates in layers
and over time
hardens
a type of sandstone
containing at least
25% feldspar
Latin word: ignis (fire)
Igneous Rocks
Process: magma, lava, crystallization
(References:)
- 2.chilton.k12.wi.us
- bc.outcrop.com
- svs.gsfc.nasa.gov
- previews.123rf.com
- learner.org
How
does it happen?
- formed when magma cools and hardens, magma
cools inside the earth, and other times it erupts onto
the surface from volcanoes (lava)
- lava cools quickly, no crystals form, looks shiny,
glasslike, gas bubbles may be trapped rock during
cooling, leaving tiny holes and spaces in the rock.
Why
is it important?
- any rock can transform to any rock, but igneous
rocks are the very first rocks on Earth. In other
words, they are the origin of rocks.
Characteristics (shiny surface, gas bubbles)
Igneous Rocks
Examples (diorite and basalt)
(Obsidian)
(References:)
- sacgeologymuseum.files.wordpress.com/2013/09/obsidian.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/pumice.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/diorite.jpg
- sacgeologymuseum.files.wordpress.com/2013/09/basalt.jpg
- learner.org
Diorite
lava cools quickly, no
crystals form and
rock looks shiny,
glasslike
Consists of
plagioclase, feldspar,
and hornblende or
other mafic minerals
Basalt
(Pumice)
gas bubbles are
trapped during
cooling , leaving tiny
holes and spaces
composed largely of
plagioclase with
pyroxene and olivine
Thank you for listening!
I am ready to answer your questions.
(Topic: Rock Cycle)
REFERENCES:
Slide 1 - Introduction
- visual.ly/rock-cycle
Slide 2 - What Drives the Rock Cycle?
- geolsoc.org.uk
- scienceblogs.com
- lauracrandler.com
- rgsenergy.com
Slide 3 - Metamorphic Rocks Process
- learner.org
- mineralogy4kids.org
- 1.bp.blogspot.com
- upload.wikimedia.org
Slide 4 - Metamorphic Rock Examples
- sacgeologymuseum.files.wordpress.com
- learner.org
Slide 5 - Sedimentary Rock Process
- cdn.shopify.com
- getfillings.com
- learner.org
- mineralogy4kids.org
Slide 6 - Sedimentary Rock Examples
- sacgeologymuseum.files.wordpress.com
- learner.org
Slide 7 - Igneous Rock Process
- 2.chilton.k12.wi.us
- bc.outcrop.com
- svs.gsfc.nasa.gov
- previews.123rf.com
- learner.org
Slide 8 - Metamorphic Rock Examples
- sacgeologymuseum.files.wordpress.com
- learner.org
Most helpful/most used sources:
- learner.org
- mineralogy4kids.org
- geolsoc.org.uk