Igneous Rocks
http://earthref.org/SCC
Scripps Classroom Connection
Mafic – magma
Partial Melting
or igneous rock
rich in
magnesium (Mg)
and iron (Fe) and
generally dark
Felsic - magma
or igneous rock
rich in feldspars
and silica and
generally light
http://earthref.org/SCC
Partial Melting – process by which different
minerals in rock melt at different temperatures
Fractional Crystallization – reversed
process of partial melting
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Bowen’s Reaction Series
http://earthref.org/SCC
Scripps Classroom Connection
Mafic Igneous
Rocks
Intermediate
Igneous Rocks
Felsic Igneous
Rocks
http://earthref.org/SCC
Scripps Classroom Connection
Extrusive – an
igneous rock
formed at the
Earth’s surface
Intrusive – an
igneous rock
formed beneath
Earth’s surface
http://earthref.org/SCC
Scripps Classroom Connection
http://earthref.org/SCC
Scripps Classroom Connection
How to classify igneous rocks:
Rock Color
Light
Dark
Felsic
Intermediate
Mafic
Ultramafic
Coarse
Granite
Diorite
Gabbro
Peridotite
Fine
Rhyolite
Andesite
Basalt
Vesicular
Glassy
http://earthref.org/SCC
Pumice
Scoria
Obsidian*
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Animations
How are the different
textures of igneous
rocks formed?
http://earthref.org/SCC
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http://earthref.org/SCC
Scripps Classroom Connection
Animations
Relation of Igneous Rocks to Plate
Tectonic Boundaries
http://earthref.org/SCC
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Mid-ocean Ridges
http://earthref.org/SCC
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Overview
Igneous rock formation
 Crystal size and other textures
 Color
Igneous rock classification
Locations where igneous rocks form
http://earthref.org/SCC
Scripps Classroom Connection