Download What are rocks?

What are rocks?
Do you remember what forms
rocks?
Atoms form Elements ….
that form….
that form....
that form….
that form…..
Classification of Rocks
•The grouping of objects that
have things in common is
called classification.
•Rocks are classified by the
way they form.
•Petrologists classify rocks
and minerals.
Classes of rocks
•Igneous Rocks
•Sedimentary Rocks
•Metamorphic Rocks
Igneous Rocks
• Igneous means “Formed by
fire”.
• Formed as magma rises through
cracks in the Earth’s crust.
• The cooled magma crystallizes
and hardens.
• Igneous rock is then formed!
• Makes up 75% of Earth’s crust.
Review!!
What is magma?
Molten rock inside the Earth.
What is lava?
Molten rock on Earth’s surface.
Which layer of the Earth contains
magma?
Mantle or asthenosphere
Classifying Igneous Rock
Scientists classify igneous rock
according to where it is
formed -- above the Earth’s
surface or below the surface.
The two types of igneous
rocks are intrusive and
extrusive.
What is the difference
between intrusive and
extrusive igneous rock?
Intrusive rock form under the
Earth’s surface. Extrusive
above the surface.
Explore!!
Examine the samples of these
igneous rocks. Identify
whether the following are
intrusive or extrusive.
Gabbro
Pumice
Granite
Rhyolite
Obsidian
Basalt
Scoria
All rocks begin as igneous
rocks.
• Igneous rock must be broken
down in order to form
sedimentary rock.
• How does this occur
Sedimentary Rock
Now that rocks are broken down
into sediments, sedimentary
rock may form.
Two ways for this type of rock to
form:
1) Formed in water from
accumulated sediments.
2) Formed from remains of living
things.
Two groups of Sedimentary Rock
• Clastic: Formed from fragments
caused by erosion and transported
by water, wind, or ice.
(Conglomerates, sandstone, shale)
• Nonclastic: Made up of dissolved
minerals or the remains of plants
and animals. (Fossils, cave
stalactites and stalagmites,
limestone)
Explore!!
Examine the samples of
sedimentary rocks.
Identify whether they are clastic
or nonclastic. I have jars of HCl
acid (diluted) that you can test
for calcium carbonate …
nonclastic.
Record qualitative and
quantitative data.
Oil Shale (1)
Gray Shale (2)
Gray Sandstone (3)
Fossil Limestone (4)
Fine Limestone (5)
Banded Sandstone (6)
Conglomerate (7)
Metamorphic Rock
• Metamorphic rocks are chemically
changed rocks.
• The heat and pressure inside the
Earth “bakes” and changes the
minerals inside rocks.
• The Earth’s oven can change
igneous, sedimentary, or even
metamorphic rocks into other
metamorphic rocks.
How are metamorphic rocks
classified?
• Foliated: Minerals are arranged in
bands. (Granite  gneiss,
Shale, basalt, or granite  schist,
Shale  slate)
• Nonfoliated: Minerals are not
arranged in bands.
(Limestone  marble,
Sandstone  quartzite)
Explore!!
Examine the samples of
metamorphic rocks.
Identify whether they are
foliated or nonfoliated.
Record qualitative and
quantitative data.
Quartzite (1)
Gneiss (2)
Mica Schist (3)
Chlorite Schist (4)
Marble (5)
Gray Sandstone (Sedimentary)
(6)
Limestone (7)