METAMORPHIC ROCKS

What is a metamorphic rock? Metamorphic rocks form

after another rock is subjected to extreme heat and/or pressure and that changes its physical characteristics

Metamorphic Rocks Appear Similar to Their Parent Rocks A metamorphic rock will

often resemble the rock it transformed from (parent rock)

Where does the heat and pressure come from? Heat and pressure can

originate from Earth’s internal heat, weight of rocks above, and folding in mountain building

How does the rock change? Minerals recrystallize or

deform

Textures of Metamorphic Rocks Foliated Nonfoliated

Foliated Metamorphic Rocks Mineral grains have

aligned due to heat and direct pressure

Sometimes the minerals are so aligned, they form bands in the rock, this is known as banding

Nonfoliated Metamorphic Rocks Mineral grains are heated

and compressed usually to a higher density

2 Types of Metamorphism Regional Local

Regional Metamorphism Metamorphism of rocks

over a large area due to pressure, common in folded mountains

Local Metamorphism Metamorphism of rocks

over a smaller area due to contact with magma