ROCKS CHANGE INTO OTHER ROCKS OVER TIME

Igneous rocks form from molten rock.

Magma and lava form different types of igneous rocks.

• Igneous rocks form from molten rock that has cooled.

• Molten rock comes from deep within the earth.

• There temperatures are hot enough to melt rock: 14000-23000 F.

• Magma vs. lava

Classifying igneous rocks

• Based on two factors: 1) mineral composition 2) size of crystals

• Rocks with larger mineral crystals are more attractive.

Intrusive

• INTRUSIVE IGNEOUS

ROCK- Rock that forms

when magma

cools within the Earth.

Extrusive

• EXTRUSIVE IGNEOUS

ROCK-Rock that forms

when lava cools

at the Earth’s

surface.

Extrusive igneous rocks

GRANITE RHYOLITE

PUMICE BASALT

GABBRO

Igneous rocks make long lasting landforms.

• Ship Rock (New Mexico)• A great peak that rises out of the flat, barren desert.• Great example of a natural feature on the Earth’s surface

(landform) that is made of igneous rocks.

Ship rock formed about 1 km below the surface of the Earth 30 million years ago. It was once intrusive igneous rock. These types of formations are harder and more lasting than other types of rock. It is now extrusive igneous rock.

Extrusive formations

• The Hawaiian islands are built of basalt lava.

• Basalt lava flows long distances.

• The volcanoes that formed them started erupting on the sea floor and over a very long time they grew tall enough to rise out of the ocean!

Extrusive formations (cont.)• Mt. Saint Helens

(Washington)• This volcano’s lava is silica

rich.• This lava builds cone

shaped volcanoes with steep sides.

• These erupt explosively since the lava is thick, sticky and under high pressure.

PICTURES COURTESY OF:• http://www.windows.ucar.edu/tour/link=/earth/geology/images/batholith_gif_image.html&edu=high• http://cc.usu.edu/~sharohl/granite.jpg• http://msnbcmedia3.msn.com/j/MSNBC/Components/Photo/_new/earth-540x540.widec.jpg• www.galleries.com• http://beyondbooks.com/ear82/7a.asp• http://www.pitt.edu/~cejones/GeoImages/2IgneousRocks/IgneousTextures/4PorphyriticFinez/RhyoliteWholeRock.jpg• http://geology.csupomona.edu/alert/igneous/pumice.jpg• http://search.live.com/images/results.aspx?

q=BASALT&go=&form=QBIR#focal=44c3c975183c8b633abce7e34c0faf8a&furl=http%3A%2F%2Fruby.colorado.edu%2F%257Esmyth%2FResearch%2FImages%2FVolcanix%2FColBasalt.jpg

• http://www.etankonyv.hu/sz_etankonyv/editor/upload/Epitoanyagok/gabbro.jpg• http://www.dkimages.com/discover/previews/919/50487851.JPG• http://www.earthskids.com/gabbi/saint-helens-plume.jpg