METAMORPHIC ROCKSMETAMORPHIC ROCKSMETAMORPHIC ROCKSMETAMORPHIC ROCKS
What are Metamorphic Rocks?
• Rock formed from existing rocks by HEAT and PRESSURE
• HEAT does not mean the rock MELTS !!!!
• Usually formed from igneous or sedimentary rock
What happens to rocks undergoing Metamorphism?
• Pressure squeezes their grains closer together
• Heat may rearrange the atoms forming new minerals
Where are types of Metamorphism?1) Regional Metamorphism
when large areas of rock are transformed by heat and pressure deep within the Earth, usually by mountain building from movements of tectonic plates.
2. Contact Metamorphism
• When magma intrudes into overlying rocks
• This magma “bakes” the surrounding rock which it makes “contact” with
.
The Metamorphic series
How do we identify Metamorphic rocks?
TEXTURE1) FOLIATED
a) Mineral Alignment: alignment ofmineral crystals.
Igneous Metamorphic
b) Banding
rocks show alternating bands of
light and dark color
Gneiss
Metamorphic Scheme ESRT pg.7
2) NON-FOLIATED: when rocks show a crystal- like appearance
Quartzite Marble
Metamorphic Scheme ESRT pg.7