Metamorphic rock

Vocabulary

• _________- change in rock due to heat and pressure

• __________- has a banded appearance

• __________- does not have a banded appearance

Let us review

• We already learned – There are three types of rocks

• Igneous rocks- – Igneous – “rock from fire”

» Made by molten rock (magam and lava) that has cooled down

• Sedimentary rocks – Sedimentary rocks – settled rocks

» Pieces of rocka nd other particles get put together to form rock

• Metamorphic rock – We shall see………………………..

From what materials are metamorphic rocks made?

• The easy answer is from ALL rocks– Whether it is

• Sedimentary • Igneous • Metamorphic

– It is a recrystallization of unmelted

– ALL of them can form into metamorphic rocks under the right conditions

What are the right conditions to form metamorphic rocks?

• Heat and pressure– Therefore metamorphic

rocks primarily can only be formed deep in the Earth’s crust

OR – Contact metamorphism –

this is when it forms because it is near a magma flow

• It gets the heat it needs from the magma

• Metamorphic rocks can change – Shape– Texture

of the original rock– Mineral composition

• Sometimes scientists can sometimes tell What the original rock was and other times they can’t – The orginal rock is called

Parent Rock

When do we see

metamorphic rock?

When the earth’s surface erodes or

weathered the metamorphic

rock is exposed

How can I tell the difference between metamorphic rocks?

• Metamorphic rocks are usually harder and more dense

• Original layers commonly get bent or distorted

• It may also show foliation – The alignment of minerals

or separation of different minerals into flaky layers or light and dark bands

Foliation vs. Non foliation

• A fantastic way to classify metamorphic rock– Foliation is very big

indicator of metamorphic rocks

– Non- foliation are classified by composition (what they are made up of)

Banding

• Different minerals give metamorphic rocks a striped appearance– separated of light and

dark minerals into layers

• The more pressure and higher temperature and pressure the thicker the band

–

Distorted structure

• Is folding or bending of rock layers – This occurs do to

strong Earth forces – Causing the rock to

have deformed appearance

Regional Metamorphism

• Makes the most of the metamorphic rock – This is caused by the

pressure that occur with mountain building

Let’s review