3. Geologists classify rocks into three major
groups depending on how they are formed:
Igneous rock, Sedimentary rock, and
Metamorphic rock.
4. • Formed from cooled Lava and Magma
As an Example:
Liquid hot lava
can become
***When the lava cools and turns into a solid, it can turn into quartz!
5. - Igneous Rocks
1. Take some Minerals &
Gasses – Mix well
2. Add Heat Energy & Melt
(cook for +/-10 thousand years)
3. Turn to Magma
(Liquid Molten Rock)
4. Cool & Crystallize
(Intrusive/Extrusive)
Minerals + Heat
5. Igneous Rock
under the
Serve and Enjoy
ground
6. • Formed inside the crust/mantle.
• These types always have large visible
crystals. (cooled slowly)
• Ex: Granite and Gabbro
This is a special kind of Granite ***Notice that both rocks have
called: “Pink Granite” easy to see crystals
7. • When magma from below rises up, but
does not make it to the surface, the
minerals start to crystallize slowly and form
large crystals. Notice the bulge that forms!
= there might be an eruption soon!
Or not…
This became Granite
Magma because it never made
it to the surface!
8. • Formed on top of the crust.
• Small, hard to see crystals (cooled quickly)
• Ex: Pumice, Obsidian
***No visible crystals in either rock
9. • When magma from below rises and
Blam!
punches through, the minerals don’t have
time to crystallizeash, gasses, they
– therefore,
volcanic glass, etc. Other types of
produce rocks with small crystals. rock can be
blasted out
Lava Flow
(Outside)
The lava will quickly
Magma cool into solid rock!
(inside)
10. • Granite and Rhyolite: can you see crystals?
Rhyolite form from
the same type of
cooled magma.
• If the magma cools
rapidly, smaller
There are no visible crystals!
crystals form and
Rhyolite rock is
Granite: can you see crystals?
produced.
• If the magma cools
slowly, larger There are lots of visible crystals!
mineral crystals form
and the type of rock
11. • Formed by sediments (pieces of rock,
shells, and dead organisms) becoming
“cemented” (stuck) together.
Sandstone Coal
Limestone Conglomerate
***You can see lots of different stuff
stuck together in these rocks!
12. 1. Rocks exposed at Rise to the
the surface Surface
Weathering
2. Weather (Break Up) & Erosion
Sedimentation
& Deposition
3. Erode (Carry Away)
Compaction
4. Sedimentation &
Deposition Cementation (stuck
together)
5. Compaction &
Cementation ***Notice that different
layers of “sediments” are forming
14. • Made from other rocks
Take notice of small
pieces of rock stuck
together
15. • Made from parts of living things.
Notice all the shells
stuck together
16. • Formed through evaporation.
• (ex: limestone)
All this Limestone used to be
on the bottom of an ocean!
(ocean floor)
***Limestone is made up of the
Calcium (shells) and Carbon (bodies) from
once living things (dead)
In fact, we call Limestone:
in the water (oceans).
Calcium Carbonate!
17. • Particles of shells/rocks stuck together
• Dull (not shiny)
• Straight layers Sandstone: pieces of sand stuck together
• Fossils (often)
The layers are going in this direction
can you see them?
18. • To “Morph” means to
•change it!have changed.
Rocks that
“…more than meets the eye!”
• They were once Igneous or
Sedimentary rocks that got buried
DEEP under ground.
• The heat and pressure from being
deep underground changed the
rocks.
• Has large, inter-grown crystals in
thin “bands” (Foliated) or clusters
(Non-Foliated).
19. 1. Get some pre-formed rock –
Igneous or Sedimentary will do.
2a. Add Heat 2b. Squeeze
“cook it” (pressure) to
“Foliate”
3. Cool & (Re)-Crystallize
Heat and pressure
4. Metamorphic
Rock!!!
Note: If it melts
completely and cools; It
will turn back into an Rocks are
Igneous Rock “Morphed”
20. • Mineral crystals aligned in parallel layers.
Notice that the crystals
have been squished into
mostly straight lines.
21. The shoes represent the pressure
caused by all the rock above
the crystals
The “playing cards” represent
mineral crystals in a rock!
Crystals are large Crystals have become “squished”
22. Crystals
Crystals are
line up in
Random in
mostly
their locations
straight lines
HE
AT
e
sur
P res Granite=large, randomly Gneiss=smaller, lined
located crystals becomes up crystals
23. • Gneiss:
• Schist:
Can you see all the
Straight layers of crystals?
• Slate:
27. Any type of rock can be
changed into any of
the other types of rock
by natural forces.
28. Review Questions
1. What are three major types of
rock found in nature?
2. All new rock starts out as what
type of rock?
3. What is the difference between
intrusive and extrusive
igneous rock?
29. Review Questions
4. How are sedimentary rocks formed?
5. Describe the three types of
sedimentary rock.
6. What three types of forces are
present when metamorphic rock
forms?
