Igneous RocksIgneous Rocks

By: AnaBy: Ana

4B4B

How the rock is formed? How the rock is formed?

• Igneous rocks are those that form by Igneous rocks are those that form by cooling from a melt. If they erupt from cooling from a melt. If they erupt from volcanoes as lava, they are called volcanoes as lava, they are called extrusiveextrusive rocks. If they cool rocks. If they cool underground but near the surface, they underground but near the surface, they are called are called intrusiveintrusive and often have and often have visible, but tiny mineral grains. If they visible, but tiny mineral grains. If they cool very slowly deep underground, they cool very slowly deep underground, they are called are called plutonicplutonic and have large and have large mineral grains.mineral grains.

Where do the Igneous Rocks fit Where do the Igneous Rocks fit into the rock cycle?into the rock cycle?

• Igneous rock forms when magma Igneous rock forms when magma cools and makes crystals. Magma is cools and makes crystals. Magma is a hot liquid made of melted minerals. a hot liquid made of melted minerals. The minerals can form crystals when The minerals can form crystals when they cool. Igneous rock can change they cool. Igneous rock can change into sedimentary or metamorphic into sedimentary or metamorphic rock.rock.

The Rock CycleThe Rock Cycle

PropertiesProperties

The two major properties used to classify The two major properties used to classify igneous rock are: igneous rock are:

1. Crystal Size1. Crystal Size

Small crystals are indicative of rapid above Small crystals are indicative of rapid above ground cooling of lava into what is classified ground cooling of lava into what is classified as extrusive igneous rock such as basalt. as extrusive igneous rock such as basalt. Large crystals are indicative of slow cooling Large crystals are indicative of slow cooling magma underground, resulting in what is magma underground, resulting in what is called intrusive igneous rock such as granite.called intrusive igneous rock such as granite.

Properties Properties

2. Chemistry or Mineralogy2. Chemistry or Mineralogy

Igneous rock, whether intrusive or Igneous rock, whether intrusive or extrusive, that is high in extrusive, that is high in silicasilica is is classified as classified as felsic.felsic. Igneous rock that Igneous rock that is low in is low in silicasilica, is classified as , is classified as maficmafic. . Rocks falling between the two are Rocks falling between the two are classified as classified as intermediate.intermediate.

Uses of Igneous RocksUses of Igneous Rocks

• Jewelry Jewelry

• Lava SoapLava Soap

• Building MaterialsBuilding Materials

• Landscaping Landscaping

• GravestonesGravestones

• Decoration on Buildings.Decoration on Buildings.

Where can this type of rock be Where can this type of rock be found?found?

• Igneous rock can be found on the Igneous rock can be found on the surface in areas of current or past surface in areas of current or past volcanism or in uplifted and eroded volcanism or in uplifted and eroded areas of past plutonic intrusions, deep areas of past plutonic intrusions, deep underground nearly anywhere, or in underground nearly anywhere, or in areas of past or present glaciation, areas of past or present glaciation, where igneous rock has been eroded where igneous rock has been eroded and deposited. and deposited.

Types of Igneous rocks?Types of Igneous rocks?

• There are many types here are some There are many types here are some ::

• Basalt Basalt

• GraniteGranite

• Obsidian Obsidian

• DuniteDunite

• TuffTuff

QuizQuiz

1.The Mount Rushmore National 1.The Mount Rushmore National Monument is carved from the granite Monument is carved from the granite of South Dakota's Black Hills. What of South Dakota's Black Hills. What type of rock is granite? type of rock is granite?

a.a. Igneous Igneous b.b. Metamorphic Metamorphic c.c. Sedimentary Sedimentary d.d. None of the above None of the above

The Answer is…..The Answer is…..

• Did you get it right ?Did you get it right ?

QuizQuiz• What type of igneous rock makes up most What type of igneous rock makes up most

of the ocean floor? of the ocean floor?

• a. Basalt a. Basalt • b. Graniteb. Granite• c. Lucite c. Lucite • d. Shaled. Shale

The Answer is ….The Answer is ….

• Did you get it right?Did you get it right?

QuizQuiz

• What rock type is formed from the What rock type is formed from the slow cooling of magma under the slow cooling of magma under the earth's surfaceearth's surface

• a. Extrusive igneousa. Extrusive igneous

• b. Intrusive igneous b. Intrusive igneous

• c. Metamorphicc. Metamorphic

• d. Sedimentd. Sediment

The Answer is ….The Answer is ….

Did you get it right ?Did you get it right ?

QuizQuiz

• Which characteristic is common to Which characteristic is common to extrusive igneous rocks? extrusive igneous rocks?

• A. Crystals A. Crystals

• B. Fossils B. Fossils

• C. Glassy surface C. Glassy surface

• D. Ribbonlike layersD. Ribbonlike layers

The Answer is ….The Answer is ….

• Did you get it right ?Did you get it right ?

Quiz (Quiz (Easy one) Easy one)

• The interrelationship among the The interrelationship among the three rock types is identified as three rock types is identified as which of the following? which of the following?

• A. The rock cycleA. The rock cycle

• B. The rock formationB. The rock formation

• C. The rock helixC. The rock helix

• D. The rock metamorphosisD. The rock metamorphosis

The Answer is …The Answer is …

• Did you get it right ?Did you get it right ?