Chapter 4: section 3
 Metamorphic
rocks are rocks that have been
changed because of changes in temperature
and pressure or due to the presence of hot
watery fluids.
 Metamorphic
rocks may form from igneous,
sedimentary rock, or other metamorphic
rocks.
 Example:
granite  gneiss
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Rocks beneath the Earth’s surface are under great
pressure from the rocks above them.
Temperature will increase with depth in the Earth.
Underneath the Earth some minerals will melt or
dissolve and recrystalize.
Example: Shale  Slate  phyllite  schist  gneiss
Each different type of metamorphic rock can come from multiple parent
rocks.
 Fluids
can move through rock and change
the rocks composition.
 Example:
 What
Water and carbon dioxide
are fluids?

Texture and mineral composition determine how a
metamorphic rock is classified.
• Foliated – layers
• Nonfoliated – no layers

Physical properties of metamorphic rocks, such as the
watertight nature of slate, make them useful for
many purposes.

Foliated Rocks
• When mineral grains line up in parallel layers, the
metamorphic rock is said to have foliated texture.
 Ex. Slate and gneiss
• Shale  slate
• Shale: (minerals arrange into layers with heat and
pressure.)
• Slate: Slate is watertight and easily split into layers
• Uses: patio and pools
 Nonfoliated
rocks describe metamorphic rock,
such as quartzite or marble, whose mineral
grains grow and grow but do not generally
form layers.
 Grains
of quartz  sandstone  quartzite