IGNEOUS ROCK• Volcanoes eject molten rock

• Molten rock=magma

• Flows when hot and becomes a solid when it cools

• Hardened, cooled magma is called igneous rock.

Magma• Temperatures of magmas range from about

650° to 1,200°C, depending on their chemical compositions and pressures exerted on them.

• Earth’s heat to melt rocks comes from interior

• Radioactive decay of elements is main source of heat.

• Magma is less dense than surrounding rock, which forces it upwards

• When magma reaches Earth’s surface and flows from volcanoes, it is called lava.

Instrusive Rocks

• Atoms and compounds in the liquid rearrange into new crystals called mineral grains, when magma cools

• Rocks form when mineral grains grow together.

• Rocks from magma below the surface are called intrusive igneous rocks.

Extrusive Igneous Rock

• Extrusive Rock forms when magma cools on Earth’s surface

• Magma exposed to air and water, thus cools quickly.

Volcanic Glass• Pumice, obsidian, and scoria are examples of

volcanic glass.

• Rocks cooled so quickly few or no mineral grains formed.

• Pumice and scoria, gases become trapped in the gooey molten material as it cools.

Basaltic Rock

• Basaltic igneous rocks are dense, dark-colored rocks.

• Rich in iron and magnesium and poor in silica.

• FE and MG gives them dark color

• Basaltic Lava is fluid and free flowing.

• http://www.youtube.com/watch?v=r3HyGTrgt7k

Granitic and Andesitic Rock• Granitic igneous rocks are light-colored

rocks of lower density than basaltic rocks.

• Thick and stiff magma, high in silica, and low in Mg and FE.

• Andesitic igneous rocks have mineral compositions between those of basaltic and granitic rocks

• Igneous rock is formed by __________.

• A. cooling of hot magma

• B. change in pressure

• C. compression of loose materials

• D. pressure from watery fluids

• What is the difference between intrusive and extrusive igneous rock?

Intrusive igneous rocks form from magma below Earth’s surface. Extrusive igneous rocks form from lava flowing at Earth’s surface.

• Which of the following is a volcanic rock that contained trapped gases during its formation?

• A. marble

• B. pumice

• C. sandstone

• D. slate

Igneous Rock Venn Diagram (22)

• Create a Venn Diagram comparing and contrasting Basaltic, Andesitic, and Granitic Rock.

• Draw a picture to illustrate the difference between the different igenous rocks.

• Write a level 1 or 2 question and its answer for EACH of the following ideas:– Igneous Rock– Lava– Instrusive rock– Extrusive rock– Volcanic glass