Transcript Rocks - Images

SC Standard 8-3.4
Explain how igneous, sedimentary and
metamorphic rocks are interrelated in the
rock cycle.
Better Stay
Awake!!!
Metamorphic Rocks
3rd Type of Rock
• Metamorphic rocks: formed when HEAT AND
PRESSURE cause chemical and structural
changes in existing rocks. (the word
metamorphic means to “change form.”) NO
MELTING!!
Structural change, heat and pressure rearrange
the minerals within the rock.
Chemical change, elements recombine to form
different crystals.
Metamorphic Rocks
Where does the heat and pressure come from to cause
these changes?
• Mountain-building forces. Plate tectonics
• Intrusions (forcible entry) of hot magma can
bake rocks as it intrudes them. Lava flows
can also bake rocks on the ground surface.
Lava or magma in contact with other rock
causes Contact Metamorphism.
Metamorphic Rocks
Classification
Classified by the arrangement of the grains
that make up the rocks.
• Foliated Rocks – Have obvious layers.
– Are formed by pressure in one direction.
Banded
• Non-Foliated Rocks – Have no visible
layers. Not banded.
– Are formed by pressure in all directions.
Foliated or nonfoliated?
Granite (igneous) = GNEISS (metamorphic)
Limestone (sedimentary) = MARBLE (metamorphic)
Shale (sedimentary) = SLATE (metamorphic)
metamorphism of shale
SHALE is the most common sedimentary rock.
Through the agents of metamorphism it changes to rocks that
are stable at higher temperatures and pressures.
These changes take place in the solid state.
GRANITE
Slate
Shale
Increasing Temperature and Pressure
Phyllite
Schist
Gneiss
Gneiss
Oh oh… thought I
said to stay awake?
Uses of Metamorphic Rocks
• Marble is used as a building material.
– The Lincoln Memorial
• Slate is used as roofing tile.
The following video is going to summarize all 3 categories of
rocks. Please pay attention.
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