Transcript Chapter 1, Section 1

CHAPTER 6, SECTION 2
Standards
3c. Students know how to explain the properties of
rocks based on the physical and chemical
conditions in which they are formed, including
plate tectonic properties.
Objective 1
Summarize 3 factors that affect whether
rock melts.
Objective 2
Describe how the cooling rate of magma
and lava affects the texture of igneous
rocks.
Classify igneous rocks according to their
composition and texture.
Objective 3
Objective 4
Describe intrusive and extrusive igneous
rock structures.
Assessment
End of Section Questions, Daily Quiz,
KEY TERMS
Create a flash card for the following
key terms (p. 129 in textbook):
Igneous Rock
Intrusive Igneous Rock
Extrusive Igneous Rock
Felsic
Mafic
If you finish early, study your flash cards!
IGNEOUS ROCK
Most
Igneous Rock (formed from
cooled magma) is crystalline
(made of crystals).
Magma forms when rocks melt.
3 Factors determine when rock
melts: temperature, pressure,
and pressure of fluids in the
rock.
IGNEOUS ROCK VIDEO CLIP
PARTIAL MELTING
Different minerals have different melting points.
 Minerals with lower melting points, melt first.
 The process of different minerals in the rock
melting at different temperatures is called
PARTIAL MELTING.

FRACTIONAL
CRYSTALLIZATION
 When
magma cools, the
opposite of partial melting
occurs: freezing.
 Different minerals have
different freezing points.
 As some minerals freeze, the
composition of the remaining
magma changes, creating
new minerals.
 This is called fractional
crystallization.
FRACTIONAL
CRYSTALLIZATION
 Crystals
that freeze/form
early tend to be the largest.
TYPES OF IGNEOUS ROCK
•Magma that
Intrusive cools deep
inside the crust
•Lava that cools
Extrusive at the Earth’s
surface
INTERACTIVE!
Create and Acrostic Poem using the word
IGNEOUS.
I
G
N
E
O
U
S

TEXTURES OF IGNEOUS ROCKS
Coarse-Grained
Fine-Grained
Other
• Intrusive
• Large, well-developed
mineral crystals
• Ex.: Granite
• Extrusive
• Small Mineral Grains
• Grains cannot be seen
with human eye
• Ex: Basalt
• Mixture of large and
small crystals
• Forms as a result of
slow cooling at first
then rapid cooling.
• Highly viscous
magma that cools
quickly results in
very few crystals
• If this magma has
little gas=GLASSY
• If this magma has
lots of
gases=VESICULAR
(holes)
TEXTURES VIDEO CLIP
QUICK CHECK!!
1.
2.
Name the 2 types of Igneous Rock:
____________________________________________
Give an example of a Course-Grained Igneous
Rock: ______________________________________
COMPOSITION OF
IGNEOUS ROCKS
 Mineral
Composition of igneous
rocks is determined by the chemical
composition of the magma from
which the rock formed.
 Three families of igneous rock:
 Felsic
 Mafic
 Intermediate
• Forms from
Magma that
has low
amounts of
silica and
lots of iron
and
magnesium
• Dark in
color
Intermediate Rock
• Forms from
Magma that
has large
amount of
Silica.
• Light
coloring
• Contains
feldspar
Mafic Rock
Felsic Rock
COMPOSITION FAMILIES
• Contains
less silica
than Felsic
but more
than Mafic
INTRUSIVE ROCK STRUCTURES
Igneous Rock masses that form underground are called
INTRUSIONS.
 5 types of intrusions:
 Batholiths—largest of all intrusions, larger than 100 km
squared, form the core of mountains
 Stocks—same as a batholith but smaller than 100 square
km.
 Laccoliths— “lake of rock”, when magma flows between
rock layers and spreads upward into a dome shape.
 Sills-when magma flows between the layers of rock and
hardens. Always parallel to the layers of rock below and
above.
 Dike-Magma that forces itself through vertical fractures
and solidifies.

EXTRUSIVE ROCK STRUCTURES
Igneous
rock masses that form on
Earth’s surface are called
EXTRUSIVE ROCK STRUCTURES.
Lava from a volcano that cools and
becomes rock is an EXTRUSIVE
ROCK STRUCTURE.
ANIMATED INTRUSIVE AND EXTRUSIVE
FEATURES
QUICK CHECK!!
1.
2.
3.
What is the difference between Intrusive and
Extrusive Rock Structures?
______________________________________________
______________________________________________
______________________________________________
What is Felsic Rock?
______________________________________________
______________________________________________
Name and Define 2 types of Intrusive Rock
Structures:
______________________________________________
______________________________________________
______________________________________________
______________________________________________
ASSESSMENT
In groups create posters for one of the following:
 Intrusive
 Extrusive
 Course-Grained
 Fine-Grained
 Felsic
 Mafic
 Intermediate
DAILY QUIZ