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Igneous Rocks. Mt. Rushmore. Half Dome, Yosemite, CA Ansel Adams. IGNEOUS ROCKS Some igneous rocks form from cooled lava that has exited Earth’s crust. Hawaii. Some Igneous rocks cool from magma inside Earth and later become exposed through pressure, uplift, and erosion!!!. - PowerPoint PPT Presentation
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Igneous RocksIgneous Rocks
Mt. Rushmore
Half Dome, Yosemite, CA
Ansel Adams
Hawaii
IGNEOUS ROCKSIGNEOUS ROCKSSome igneous rocks form from cooled Some igneous rocks form from cooled lava that has exited Earth’s crustlava that has exited Earth’s crust
Half Dome, Half Dome, Yosemite, Yosemite, CaliforniaCalifornia
Some Igneous rocks cool from Some Igneous rocks cool from magma inside Earth and later magma inside Earth and later become exposed through become exposed through pressure, uplift, and erosion!!!pressure, uplift, and erosion!!!
IgneousIgneousThink of “igniteignite”
To light a fire IgneousIgneous rock comes from the
heatheat within EarthEarth: Geothermal
Think of “igniteignite”To light a fire
IgneousIgneous rock comes from the heatheat within EarthEarth: Geothermal
How are Igneous Rocks Classified?
How are Igneous Rocks Classified?
Igneous rocks are classified by: 1. Mineral Composition 1. Mineral Composition 2. Crystal Size (Texture)2. Crystal Size (Texture)
Igneous rocks are classified by: 1. Mineral Composition 1. Mineral Composition 2. Crystal Size (Texture)2. Crystal Size (Texture)
Igneous Rock FormationIgneous Rock FormationMost Igneous rocks form directly
from Magma which is hot, molten rock
Granite is the most common igneous rock, it cooled from magma
Igneous rocks can also form from lava
Most Igneous rocks form directly from Magma which is hot, molten rock
Granite is the most common igneous rock, it cooled from magma
Igneous rocks can also form from lava
3. First Classification of Magma:3. First Classification of Magma:Felsic
Is rich in Silica (SiO2)
Small amounts of Ca, Fe, Mg (Calcium, Iron, & Magnesium)
Slow-moving, thick= HIGH VISCOSITY (resistance to flowing)
Crystallizes to light-coloredlight-colored minerals Resulting rocks have relatively low densitylow density Felsic rocks make up the continentscontinents
Felsic Is rich in Silica (SiO2)
Small amounts of Ca, Fe, Mg (Calcium, Iron, & Magnesium)
Slow-moving, thick= HIGH VISCOSITY (resistance to flowing)
Crystallizes to light-coloredlight-colored minerals Resulting rocks have relatively low densitylow density Felsic rocks make up the continentscontinents
Rhyolite Pumice
Examples of FELSIC igneous rocks
Examples of FELSIC igneous rocks
Mafic Low amounts of SilicaSilica (SiO2) Fe and Mg rich (Iron and Magnesium) FastFast-moving, thinner= LOW Viscosity:
less resistance to flowing, more fluid Crystallize to dark-coloreddark-colored minerals Resulting rocks have relatively high high
densitydensity Mafic rocks make up the ocean floorsocean floors
Mafic Low amounts of SilicaSilica (SiO2) Fe and Mg rich (Iron and Magnesium) FastFast-moving, thinner= LOW Viscosity:
less resistance to flowing, more fluid Crystallize to dark-coloreddark-colored minerals Resulting rocks have relatively high high
densitydensity Mafic rocks make up the ocean floorsocean floors
4. Second Classification of Magma:4. Second Classification of Magma:
Mafic Igneous Rock examples:Mafic Igneous Rock examples:
Basalt (ocean floor)
Gabbro
5. Crystal Size5. Crystal Size It takes timetime to grow crystals
As magma cools, it crystallizescrystallizes
If magma cools slowlyslowly, what size crystals will form?
It takes timetime to grow crystals
As magma cools, it crystallizescrystallizes
If magma cools slowlyslowly, what size crystals will form? Large Crystals
If If MagmaMagma cools cools quicklyquickly, , small crystals small crystals will form because they have will form because they have littlelittle time time to grow.to grow.
If If MagmaMagma cools cools quicklyquickly, , small crystals small crystals will form because they have will form because they have littlelittle time time to grow.to grow.
Igneous RockIgneous Rock
Obsidian is dark in color due to iron oxides.
ObsidianObsidian cools cools so fast that no so fast that no crystals have crystals have time to formtime to formA.K.A. Volcanic A.K.A. Volcanic glassglass
ObsidianObsidian cools cools so fast that no so fast that no crystals have crystals have time to formtime to formA.K.A. Volcanic A.K.A. Volcanic glassglass
6. Igneous Rocks6. Igneous RocksIntrusiveIntrusive
Igneous rock that crystallizes below Earth’s surface, from magma
Intrusive= Inside Earth
IntrusiveIntrusive Igneous rock
that crystallizes below Earth’s surface, from magma
Intrusive= Inside Earth
Granite
Large Crystal sizeLarge Crystal sizeLarge Crystal sizeLarge Crystal size
Notice how Granite has large crystals, it cooled Notice how Granite has large crystals, it cooled slowly from magma deep beneath Earth’s surfaceslowly from magma deep beneath Earth’s surface
Igneous RocksIgneous RocksExtrusiveExtrusive
Igneous rock that crystallizes or forms at Earth’s surface, from lava
Extrusive= exited Earth
ExtrusiveExtrusive Igneous rock
that crystallizes or forms at Earth’s surface, from lava
Extrusive= exited Earth
Basalt
Small Crystal sizeSmall Crystal sizeSmall Crystal sizeSmall Crystal size
Notice how basalt has small crystals, it Notice how basalt has small crystals, it cooled quickly at Earth’s surfacecooled quickly at Earth’s surface
LavaLava is is magmamagma that has reached the Earth’s surface.
Igneous RocksIgneous Rocks
EXT-rusive EXITED
Earth
IN-trusive Formed
IN-side Earth
EXT-rusive EXITED
Earth
IN-trusive Formed
IN-side Earth
Crystal SizeCrystal SizeCrystal SizeCrystal Size
Intrusive Rock (Large Crystal Size)
Because it is inside the Earth, it cools very slowly, giving crystals time to grow
Extrusive Rock (Small crystal size)
Cools very quickly so crystals do not have time to form
Intrusive Rock (Large Crystal Size)
Because it is inside the Earth, it cools very slowly, giving crystals time to grow
Extrusive Rock (Small crystal size)
Cools very quickly so crystals do not have time to form
Composition (what it’s made of) of GraniteComposition (what it’s made of) of GraniteGranite Rock contains the Granite Rock contains the following minerals:following minerals:
QuartzQuartz
FeldsparFeldspar
MicaMica
Granite Rock contains the Granite Rock contains the following minerals:following minerals:
QuartzQuartz
FeldsparFeldspar
MicaMica
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
Igneous RockIgneous RockFelsic(Light Color)Continents
Mafic(Dark Color)Ocean Floor
IntrusiveCools slowly
From Magma
Large crystals
(SiO2) rich
Large crystals
Fe, Mg rich
ExtrusiveCools quickly
From Lava
Small or no crystals
(SiO2) rich
Small or no crystals
Fe, Mg rich
IGNEOUSIGNEOUS
FELSIC Light colored Less dense Rich in silica (SiO2) Magma flows slowly, thick Continental crust
FELSIC Light colored Less dense Rich in silica (SiO2) Magma flows slowly, thick Continental crust
IGNEOUSIGNEOUS
MAFIC Dark colored Very dense Rich in iron (Fe) and magnesium (Mg) Magma flows quickly, thin Oceanic crust
MAFIC Dark colored Very dense Rich in iron (Fe) and magnesium (Mg) Magma flows quickly, thin Oceanic crust
IGNEOUSIGNEOUS
EXTRUSIVE “exit” Magma exits the Earth before cooling Cools and crystalizes quickly Small or no crystals
EXTRUSIVE “exit” Magma exits the Earth before cooling Cools and crystalizes quickly Small or no crystals
INTRUSIVE “in” Magma cools inside the Earth Cools and crystalizes slowly Large crystals
INTRUSIVE “in” Magma cools inside the Earth Cools and crystalizes slowly Large crystals
IGNEOUSIGNEOUS
Igneous Rock LabIgneous Rock Lab Use your Igneous observations sheet Rotate independently between the 25 stations
set up around the room Start with whichever station number you are
located Round 1: You will have less than 1 minute
at each station Do not switch to the next station until told to do
so, only 1 person at at station (if you have extra time, study your notes)
Round 2: You may go back to any unoccupied station, if needed
Use your Igneous observations sheet Rotate independently between the 25 stations
set up around the room Start with whichever station number you are
located Round 1: You will have less than 1 minute
at each station Do not switch to the next station until told to do
so, only 1 person at at station (if you have extra time, study your notes)
Round 2: You may go back to any unoccupied station, if needed
