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Metamorphic Rocks
Chapter 5
• Metamorphic rocks are rocks that have been
altered due to heat, pressure and/or chemical
fluids
• The original rock is called the parent rock
• The metamorphosed rock is known as the
daughter rock
Parent Rock Example
Daughter Rock Example
(May be igneous, sedimentary or
metamorphic)
(Metamorphic rock)
Sandstone (Sedimentary)
Quartzite
Limestone (Sedimentary)
Marble
Granite (Igneous)
Gneiss
Metamorphic Rocks
• During alteration, rocks are re-crystallized
and new minerals may form from old
minerals
• Layering, or foliation,
within metamorphic rocks
appears when rocks
experience pressure in one
direction.
• Minerals align themselves
perpendicularly to the
direction of pressure
• Not all metamorphic rocks display foliation
Metamorphic Rocks
Foliation
• There are two types of metamorphism:
– Regional
– Contact
• Regional metamorphism is widespread and
occurs during mountain-building events.
• Rocks in this area experience high heat and
high pressure.
Metamorphic Rocks
• Contact metamorphism affects rocks in
contact with liquid magma. These rocks
experience high heat but low pressure
Rocks & Minerals