Transcript Igneous Rocks

Table of Contents
Chapter: Rocks
Section 1: The Rock Cycle
Section 2: Igneous Rocks
Section 3: Metamorphic Rocks
Section 4: Sedimentary Rocks
Chapter 3 Vocabulary
• Due on Tuesday 11/18th
• Last word is cementation
The Rock Cycle
1
What is a rock?—Common Rocks
• A rock is a mixture of minerals, rock
fragments, volcanic glass, organic matter, or
other natural materials.
• * Volcanic Glass- is the uncrystallized
product of rapidly cooling magma.
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The Rock Cycle
• It is a model that illustrates the processes that
create and change rocks, over time.
• During the rock cycle, a rock from any group
can change into a rock from another group.
• Igneous, Metamorphic and Sedimentary
Rock Cycle
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The Rock Cycle Graphic Organizer
*Rocks change due to different processes .
Weathering and erosion
Melting
Heat and pressure
Cooling
Compaction and cementation
Different colors to represent the diff. processes
1
The Rock Cycle Graphic Organizer
Sedimentary and igneous rocks can change
by heat and pressure to form a metamorphic
rock.
The metamorphic, sedimentary and igneous
rocks can melt to form magma and cool to
form an igneous rock.
The Rock Cycle
1
• The igneous, metamorphic and sedimentary
rocks can be broken into fragments by
weathering and erosion.
• The fragments might later compact and
cement together to form another sedimentary
rock.
The Principle of Conservation
of Matter
• “In nature, nothing is created nor destroyed”
• Anything in nature is transformed into other
substances in a never ending cycle
The Rock Cycle
1
Matter and the Rock Cycle
The rock cycle illustrates the Principle of
Conservation of Matter.
• The changes that take place in the rock cycle
never destroy or create matter.
• The elements are just redistributed in
other forms.
• Section Review
Table of Contents
Chapter: Rocks
Section 2: Igneous Rocks
1)What is magma and why is it forced
towards the surface of the Earth?
2)What is the difference between lava and
magma?
3)Explain the difference of intrusive and
extrusive rocks.
4) Create a graphic organizer to explain the
differences between the 3 types of Igneous
rocks.( basaltic, granitic and andesitic)
1)What is magma and why is it forced
towards the surface of the Earth?
2)What is the difference between lava and
magma?
2
Formation of Igneous Rocks –
ignis ( latin) = fire
• *Magma – hot, melted rock material from
deep below the Earth’s surface that is
expelled from volcanos.
• When hot magma
cools and
hardens, it forms
igneous rocks.
Igneous Rocks
2
Magma
• Magma is forced upward toward the surface
because it is less dense than surrounding solid
rock.
• When magma
reaches Earth’s
surface and flows
from volcanoes, it
is called lava.
Mineral Grains
Atoms and compounds in the magma
rearrange themselves into new crystals
but small in size ( grain) called mineral
grains.
Rocks form as these mineral grains grow
together.
3)Rocks can be classified in intrusive and
extrusive rocks, depending on how they are
formed. Explain the difference between
intrusive and extrusive rock.
Igneous Rocks
2
Intrusive Rocks
• Rocks that form
from magma below
the surface are
called intrusive
igneous rocks.
• They cool slowly so
they form large
mineral grains
Igneous Rocks
2
Extrusive Rocks
• Extrusive igneous
rocks are formed as
lava cools on the
surface of Earth.
• They cool fast so the
mineral grains are
small and the rock is
fine grained.
4) Rocks can also be classified by the magma
from which they form. Create a graphic
organizer to explain the differences between
the 3 types of Igneous rocks: basaltic,
andesitic, or granitic
Igneous Rocks
2
Basaltic Rocks
• Basaltic igneous rocks are dense, darkcolored rocks because they form
from magma that is rich in iron and
magnesium
• Basaltic lava is fluid and flows freely from
volcanoes in Hawaii, such as Kilauea.
Igneous Rocks
2
Granitic Rocks
• Granitic igneous rocks are light-colored
rocks.
• Granitic magma
is thick and stiff
and contains lots
of silica but lesser
amounts of iron
and magnesium.
Igneous Rocks
2
Andesitic Rocks
• Andesitic igneous rocks have mineral
compositions between those of basaltic and
granitic rocks.
• Rocks can be:
• basaltic, granitic and andesitic intrusive
• basaltic, granitic and andesitic extrusive
• See page 64 Table 1
• Chapter 3 Section 2 Review page 65 1
through 4.
Table of Contents
Chapter 3: Rocks
Section 3: Metamorphic Rocks
Meta and morph, in Greek means to change
form
You need to know what is in the PPT. – link to
PPt on the web page.
Metamorphic Rocks
3
Formation of Metamorphic Rocks
• Metamorphic rocks form from igneous,
sedimentary, or other metamorphic rocks.
• Heat, pressure, and hot fluids trigger
the changes.
Metamorphic Rocks
3
Formation of Metamorphic Rocks
• The changes that occur in a rock can be:
• in the form of the rock ( from one type of
rock to another)
• the composition of the rock, or both.
Metamorphic Rocks
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Formation of Metamorphic Rocks
• Rocks beneath the Earth surface are under
heat and pressure.
• 2 things can happen:
Metamorphic Rocks
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a) Thru heat and pressure, rocks that do not
melt, can suffer changes in their chemical
composition and become a metamorphic rocks
b) By exposure to heated fluids, the mineral
grains can dissolve, mix with these fluids,
change composition and recrystallize into
metamorphic rocks
Metamorphic Rocks
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Classifying Metamorphic Rocks
• Metamorphic rocks can be classified
according to its composition and texture.
Remember: Mineral Grains
• Atoms and compounds in the magma
rearrange themselves into new crystals,
but small in size ( grain like ) called
mineral grains.
• Rocks form as these mineral grains grow
together.
Metamorphic Rocks
3
Foliated Rocks
Slate
• When mineral grains
line up in parallel layers,
the metamorphic rock is
said to have a foliated
texture.
• Two examples of foliated rocks are slate and
gneiss
Foliated: sedimentary shale transforms into
metamorphic slate
Foliated Rocks
3
Igneous Granite will turn into Gneiss
Foliation in gneiss shows up as alternating
light and dark bands.
Nonfoliated Rocks
3
• In some metamorphic rocks, layering does
not occur.
• The mineral grains grow and rearrange, but
they don’t form layers.
• This process produces a nonfoliated
texture.
Nonfoliated Rocks
3
• Sandstone is a sedimentary rock that’s often
composed mostly of quartz grains.
It turns into the metamorphic rock
quartzite
Metamorphic Rocks
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Nonfoliated Rocks
• the sedimentary rock limestone will
transform into marble