Brought to you by teachers of Cobb County, Thanks! Modifications have been made to the show. Students will classify rocks based on process of formation

1. S6E5. Obtain, evaluate, and communicate information to show how Earth’s surface is formed.S6E5. Obtain, evaluate, and communicate information to show how Earth’s surface is formed.
c. Construct an explanation of howc. Construct an explanation of how
to classify rocks by their formationto classify rocks by their formation
Objective: Students will completeObjective: Students will complete
the graphic organizer aboutthe graphic organizer about
formation of igneous rocksformation of igneous rocks
Directions: Read each slide thenDirections: Read each slide then
complete the graphic organizer.complete the graphic organizer.

2. Rock Classification
Rocks are divided into three main classes
based on how they form:
1. Igneous
2. Sedimentary
3. Metamorphic
Each type of rock can be further
classified based on:
 Composition and texture

3. Composition
 The chemical make up of the rock or
what it is made of.
 This can be minerals or other
materials: shells, clay, plants,
sand, pebbles

4. Texture/Grains
 Determined by the grains size, shape
and position.
 Igneous can be fine or coarse grain
 Sedimentary can be characterized by
observing lithified (cemented) inorganic
grains, minerals, organic material, or
fossil fragments. The wide range of
textures common in sedimentary rocks is
separated into clastic, chemical, and
bioclastic (biochemical) groups.

5. Texture/Grains
Metamorphic textures consist of
two main types: foliated and
non-foliated textures.
Texture can reveal the
process that formed the rock.

6. Igneous RocksIgneous Rocks

7. What are they?What are they?
 Rock made from cooledRock made from cooled
–LAVA, above ground orLAVA, above ground or
–MAGMA, below groundMAGMA, below ground ..

8. ClassificationClassification
They are classifiedThey are classified
in 3 ways:in 3 ways:
1.1.Texture – Grain/Texture – Grain/
mineralsminerals
2.2.Origin - where formedOrigin - where formed
3.3.Mineral Composition –Mineral Composition –
made frommade from

9. Grain SizeGrain Size Have….Have….
SPECIALSPECIAL
NAMESNAMES

10. Texture/GrainTexture/Grain
 CoarseCoarse Grained = large grains, cooledGrained = large grains, cooled slowlyslowly
Think about it…. If it cools over a long time – the grains have time to get big!Think about it…. If it cools over a long time – the grains have time to get big! 
Most abundant intrusive rock isMost abundant intrusive rock is GRANITEGRANITE
 FineFine Grained = small grains, cooledGrained = small grains, cooled fastfast
Think about it… If it cools over a short time – the grains don’t have time to get big!Think about it… If it cools over a short time – the grains don’t have time to get big!
Example:Example: BasaltBasalt

11. Igneous Rock Formation-OriginIgneous Rock Formation-Origin
 ExtrusiveExtrusive – formed ABOVE– formed ABOVE
GROUND. It coolsGROUND. It cools fastfast so it hasso it has
smallsmall grains.grains.
 IntrusiveIntrusive – formed– formed
UNDERGROUND. It coolsUNDERGROUND. It cools slowlyslowly soso
it will haveit will have largelarge grains.grains.
Laccolith

12. Examples of each type of ROCK Fine
Grained
Basalt = Extrusive Igneous rock
Course Grained
Granite = Intrusive Igneous rock

13. Mineral CompositionMineral Composition
 How much silica is in the magma/lava?How much silica is in the magma/lava?
–Low silica content = dark colored =
MaficMafic
– HighHigh silica content =silica content = lightlight colored =colored =
Felsic
High Silica Content Low Silica Content
Felsic Igneous Rock Mafic Igneous Rock

14. Lighter
Darker
Big Crystals Small or No Crystals
Draw pictures of the different types of Igneous Rocks!

15. Label the igneous rockLabel the igneous rock
formationformation

16. Ticket out: CHOOSE ONLYTicket out: CHOOSE ONLY
ONEONE
 What makes up the grains in
an igneous rock?
Illustrate grains of an igneous
rock and explain why this
happens
Compare and contrast
intrusive and extrusive igneous