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Rocks!
Goal 2.1
Lesson 2
Igneous Rocks
Think About It…
What is the ultimate source of
all solid, non-living material
on Earth?
Focus Question…
How are igneous rocks
formed, classified, and used?
About Igneous Rocks…
• Meaning of the
word igneous…
– Igneous is
Latin for fire!
Volcano in the Philippines
http://news.bbc.co.uk/2/hi/in_pictures/5198238.stm
How Igneous Rocks Form …
• How do igneous rocks form? 1. Igneous rocks are
formed from the crystallization of magma.
2. Three factors that affect magma formation are
1. temperature
2. pressure
3. water content
http://news.bbc.co.uk/2/hi/in_pictures/5198238.stm
Practical Uses of Igneous
Rocks… Practical Uses of Igneous Rocks…
1. As construction materials – granite
2. As valuable ore deposits – silver, gold, lead, copper
3. Pegmatites contain gemstones
4. Kimberlites contain diamonds. See next slide.
http://www.granite-counter-tops.org/granite-sink-424.jpg
Granite countertop
http://gccweb.gccaz.edu/earthsci/imagearchive/PEGMATITE_tn.jpg
Pegmatite
A Giant Amethyst – Washington
DC
Kimberlites • In South Africa in the
1860’s, it was
discovered that
kimberlites were the
source of diamonds.
http://www.diamond-all.com/Diamond.html
Classification of Igneous
Rocks E
X
T
R
U
S
I
V
E
Felsic Intermediate Mafic Texture
I
N
T
R
U
S
I
V
E
-------
----------
--------
For pictures, see next slide…
obsidian and pumice
Basaltic glass
glassy
rhyolite andesite basalt fine
gabbro coarse granite
pegmatite
Very coarse
Extrusive
Rocks… o Pumice (glassy)
o Obsidian (glassy)
o Basalt (fine grained)
o Small to no crystals!
(glass)
http://geology.com/rocks/pumice.shtml
Hawaii’s Black Sand Beach – Eroded Basalt…
Intrusive
Rocks…
• Granite (coarse)
• Gabbro (coarse)
• Diorite (coarse)
• Large to very large
crystals!
diorite
granite
gabbro
Mount Rushmore – Granite
Faces!
Hawaii’s Green Sand
Beach…Eroded Olivine
www.lovingthebigisland.wordpress.com
www.skywalker.cochise.edu
Compare Extrusive to
Intrusive… • Both are mafic.
• Basalt cooled above
ground.
• Gabbro cooled
underground.
gabbro
basalt
Compare Extrusive
to Intrusive… • Both are felsic.
• Obsidian cooled
above ground.
• Granite cooled
underground.
granite
obsidian
Lesson 3
Sedimentary Rocks
Think About It…
What would happen to an
animal if it fell into lava?
Focus Question…
How are sedimentary rocks
formed, classified, and used?
About Sedimentary Rocks…
• The word
“sediments”
means…
– Pieces of solid
material
deposited on
Earth’s surface
http://science.nasa.gov/science-news/science-at-nasa/2001/ast23jan_1/
Types of Sediment
(smallest to biggest) • Clay
• Silt
• Sand
• Pebbles or gravel
http://techalive.mtu.edu/meec/module06/SoilClassification.htm
Types of Sediment
(smallest to biggest)
http://school.discoveryeducation.com/schooladventures/soil/name_soil.html
How Sedimentary Rocks
Form…
1.Rocks are weathered meaning…
–Big pieces are broken down into smaller pieces. Arches National Park in Utah –
weathered rocks become arches!
http://www.nationaloutdoors.net/files/images/arches_national_park.gif
How Sedimentary Rocks
Form…
2.Sediments are
eroded
meaning…
They are
removed to
another
location.
http://drake.marin.k12.ca.us/stuwork/rockwaterl
How Sedimentary Rocks
Form…
3.Sediments are
deposited
meaning…
– They are put
down
somewhere
else. Deposition of sediments
along a stream http://ag.arizona.edu/extension/riparian/chapt4/p5.html
How Sedimentary Rocks
Form…
4. Sediments are
buried.
How Sedimentary Rocks
Form…
5. Sediments are
lithified or turned
into stone by the
processes of…
a. compaction
b. cementation
http://faculty.ksu.edu.sa/alhomadhi/Sandstone/Forms/DispForm.aspx?ID=14
Sedimentary Rocks in the
Badlands (South Dakota)
Sedimentary Rock (Layers and
Erosion) – Badlands, S. Dakota
Importance of Sedimentary Rocks…
1. Sedimentary rocks
often contain
fossils which can
give us clues to the
past.
A trilobite preserved in sedimentary rock. http://www.fossilsforkids.com/
Aunt Pearl’s Fossil Farm East Tennessee
http://www.grayfossilmuseum.com/
http://www.grayfossilmuseum.com/?CONTEXT=art&cat=25&art=85&BISKIT=1941568670
Aunt Pearl’s Fossils (Short-face Bear)
http://boneblogger.com/how-big-was-the-giant-short-faced-bear/
Aunt Pearl’s Fossils (Saber Tooth Cat)
http://igs.indiana.edu/FossilsAndTime/Sabertooth.cfm
Aunt Pearl’s Fossils (Red Panda)
http://en.wikipedia.org/wiki/File:RedPandaFullBody.JPG
Aunt Pearl’s Fossils (Tapir) http://www.zooborns.com/zooborns/2013/01l
http://tapirs.org/tapirs/
Importance of Sedimentary Rocks…
2. Energy sources
(fossil fuels) such
as
1.oil
2.natural gas
3.coal
Sedimentary rock layers with petroleum and
natural gas deposits.
http://teeic.anl.gov/images/photos/third_stage_OG_formation.gif
Open-pit Coal Mine (Wyoming)
Coal-burning Power Plant –
Jacksonville, FL
Importance of Sedimentary Rocks…
3. Uranium, a
nuclear fuel, is
found in the
sedimentary
rock known as
sand stone.
Uranium containing sandstone found in
Colorado
http://www1.newark.ohio-state.edu/Professional/OSU/Faculty/jstjohn/Minerals/Carnotite.htm
Importance of Sedimentary Rocks…
4. Limestone is
processed to
make cement
for the
construction
industry.
Miami limestone!
http://www.dep.state.fl.us/geology/geologictopics/rocks/miami_limestone.jpg
Corvette Museum Sinkhole…
http://www.usatoday.com/story/money/cars/2014/02/21/corvette-museum-sinkhole/5674659/
Classification of Sedimentary Rocks… Clastic (broken)
1. Coarse-grained- conglomerate (gravel/pebbles)
2. Medium-grained – sandstone (sand)
3. Fine-grained – shale (clay)
4. These form when broken pieces of sediment are cemented together.
conglomerate sandstone shale
Classification of Sedimentary Rocks…
Chemical
1. Calcite - limestone
2. Halite – rock salt
3. Gypsum – rock gypsum
4. These form when water evaporates leaving the rock behind.
limestone halite
Classification of Sedimentary Rocks… Organic (from living things)
1. Shells – coquina limestone (shells & calcium carbonate)
2. Plant matter (swampy) – coal
3. These form from living things that get turned into
rock!
coquina limestone coal
http://www.dep.state.fl.us/geology/geologictopics/rocks/miami_limestone.jpg
Coquina Rocks in North Florida…
Coquina in
North Florida
www.uky.edu
Most of the coal burned in the USA is bituminous.
Lesson 4
Metamorphic Rocks
Think About It…
What happens to a caterpillar
during metamorphosis?
Focus Question…
How are metamorphic rocks
formed, classified, and used?
About Metamorphic Rocks…
• Metamorphic is
Greek for…
– change in
form
http://www.yourdictionary.com/images/main.metamorphosis.jpg
How Metamorphic Rocks
Form…
A metamorphic rock forms when high temperatures
and pressure combine to alter the texture,
mineralogy, or chemical composition of a rock
WITHOUT MELTING IT!
• Link to view a visualization of the process…
• http://www.classzone.com/books/earth_science/terc
/content/visualizations/es0607/es0607page01.cfm?
chapter_no=visualization
How Metamorphic Rocks
Form…
• Three types of
metamorphism may
change rocks…
a. Regional
b. Contact
c. Hydrothermal
http://www.fi.edu/fellows/fellow1/oct98/create/metamorph.htm
Practical Uses of
Metamorphic Rocks…
1. Contain economically
valuable minerals –
talc and garnets
2. Marble is used in
sculpting.
3. Deposits of gold, and
lead are formed by
metamorphism.
http://facstaff.gpc.edu/~pgore/geology/geo101/meta.htm
http://gurneyjourney.blogspot.com/2009/01/arc-of-hollows.html
Monument in Marble (GA white and TN)…
David…
http://www.firenzeturismo.it/aptgest/images/stories//musei//0056-al_accademia_david_di_michelangelo.jpg
Classification of Metamorphic Rocks…
• Foliated…
– Have wavy layers or bands that are caused by minerals with flat crystals that form long axes perpendicular to the pressure
1. Slate from shale
1. Schist from shale (buried
deeper)
2. Gneiss from granite
Mount Rushmore – Also contains mica
schist
Classification of Metamorphic Rocks…
• Nonfoliated…
– Lack mineral grains with long axes in one
direction. They form minerals that have
blocky crystal shapes.
2. Marble from limestone
1. Quartzite from sandstone
3. Hornfels from basalt
Bituminous Coal Morphs into Anthracitic
Coal…
Lesson 5
The Rock Cycle
Think About It…
How could you turn any rock
into an igneous rock?
Focus Question…
What are the processes that
turn one rock into another?
The Rock Cycle…
• How are igneous rocks formed?
– By melting, cooling, and crystallization
• What happens to igneous rocks that undergo
weathering and erosion?
– They become sediments
• How do sediments become sedimentary rocks?
– By deposition, burial, and lithification
(compaction and cementation)
The Rock Cycle (continued)…
• What forces cause sedimentary rocks to be
transformed into metamorphic rocks?
– Heat and pressure – without melting!
• How can metamorphic rock be transformed into
igneous rock?
– By melting, cooling and crystallization of
magma
• How can sandstone be transformed into
sediment?
– By weathering and erosion
The Rock Cycle…
http://www.personal.psu.edu/cll161/insys%20441/images/rock_cycle.jpg
The Rock Cycle – An
Animation…
http://www.learner.org/interactives/rockcycle/diagram.html
http://www.cotf.edu/ete/modules/msese/earthsysflr/rock.html
The Mystery of the Sliding Rocks…
• http://geology.com/nasa/racetrack-playa/