Igneous Rocks
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Vocabulary:
magma - molten rock within the crust or mantle of the earth. It is composed of various elements
and compounds that may come from the melting of other rocks.
and compounds that may come from the melting of other rocks.
extrusive - when magma flows to the earth's surface and becomes lava, ash, or any other form
of volcanically ejected material. Rock formed this way is known as intrusive igneous rock.
of volcanically ejected material. Rock formed this way is known as intrusive igneous rock.
intrusive - when magma cools beneath the earth's surface. Rock formed this way is known as
an intrusive igneous rock.
an intrusive igneous rock.
| Two Classifications of Igneous Rocks |
Extrusive Igneous Rocks
Extrusive igneous rocks occur when magma reaches the surface of the crust and exits through a fissure or a
volcano. It may extrude (come out) as a molten liquid called lava or as fine particles called tephra.
To learn more about extrusive igneous rocks, click here: Extrusive Igneous Rocks.
volcano. It may extrude (come out) as a molten liquid called lava or as fine particles called tephra.
To learn more about extrusive igneous rocks, click here: Extrusive Igneous Rocks.
Intrusive Igneous Rocks
tephra - particles erupted from a volcano that have not formed a rock. The term used to
describe a loose deposit of material is unconsolidated.
describe a loose deposit of material is unconsolidated.
lava - molten magma that flows onto the surface of the crust.
Intrusive igneous rocks are formed deep beneath the earth's surface when magma cools. When it cools slowly,
example of an intrusive igneous rock.
To learn more about intrusive igneous rocks, click here: Intrusive Igneous Rocks.
example of an intrusive igneous rock.
To learn more about intrusive igneous rocks, click here: Intrusive Igneous Rocks.