Transcript Chapter 3, Section 5 Metamorphic Rocks

Chapter 3, Section 5
Metamorphic Rocks
Wednesday, January 6, 2010
Pages 90 -- 92
Objectives
• Describe the conditions under
which metamorphic rocks form
• Identify the ways in which
geologists classify metamorphic
rocks
Vocabulary Word
• foliated
How Metamorphic
Rocks Form
• Heat and pressure deep beneath
Earth’s surface can change any
rock into metamorphic rock.
• Metamorphic rock can form out of
igneous, sedimentary, or other
metamorphic rocks.
Heat Forming
Metamorphic Rock
• Forces inside Earth can push the rock down
toward the heat of the mantle.
• Pockets of magma rising through the crust
provides this heat.
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granite
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gneiss
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shale
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slate
Pressure Forming
Metamorphic Rock
• The deeper rock is buried in the crust,
the greater the pressure on that rock
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Classifying Metamorphic
Rocks
• Geologists classify
metamorphic rocks by
the arrangement of the
grains that make up the
rock.
– When the grains are
arranged in parallel
layers or bands, they are
FOLIATED.
– Examples include slate
and gneiss.
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Slate
• Common foliated
rock.
• Came from
sedimentary rock
Shale.
• Becomes slate with
the addition of heat
and pressure.
– Mica and hornblende
form in the slate.
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Non-foliated Metamorphic
Rocks
• Mineral grains are arranged randomly.
• Marble and quartzite are examples.
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Sandstone
Quartzite
Uses of Metamorphic Rocks
• Marble and slate are the two most useful.
– Building material.
– Materials used for statues.
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Homework
• Workbook 3.5 (due 1/8)
• Vocabulary quiz 3.5 (1/8)