Metamorphic Rocks
Meta = form
Morph = change
3 Main Types
Regional Metamorphism
 Occurs in large areas due to pressure and heat
 Occurs during mountain building
 Rocks are squeezed, making them more dense and less
porous
 Atoms can be rearranged forming new minerals
 Examples: Limestone
marble
Sandstone quartzite
Shale slate
phyllite
schist
gneiss
Contact Metamorphism
 Due to heat when hot magma comes in contact with other
rocks (magma actually touches rock)
 Changes are less drastic
 Covers a smaller area
 Examples: Hornfels
Hydrothermal Metamorphism
 Hot water reacts with rock and alters it’s mineral content
o Dissolve
o Break down
o Deposit new minerals
 Occurs often near volcanoes and igneous intrusions
3 New Shapes
1. Foliated – very flat layers, sometimes light and dark
a. Shale
b. Slate
c. Phyllite
d. Schist
e. Gneiss
2. Non-foliated – large, blocky crystals
a. Quartz
b. Marble
3. Porphyroblasts – large and small pieces, from the
reorganization of atoms in solid rock during contact and
regional metamorphism
a. Garnet