AIM: What are Metamorphic Rocks
Do Now: Take out your ESRT and turn to page 7.
Look at the chart called Scheme for Metamorphic
Rock identification and answer the questions
below.
1) What textures of Metamorphic rocks will we be
working with?
2) What types of metamorphism are there?
I. Formation of Metamorphic Rocks
- Metamorphism – “to change form”
- high temperatures and pressures beneath the
surface causes pre-existing rocks to change.
- created from other rocks; igneous sedimentary and
metamorphic
Schist
Slate
Gneiss
A. Contact Metamorphism –
takes place in a small area
when hot magma moves into
rock and touches the rock.
*This symbol indicates contact
metamorphism took place
B. Regional Metamorphism –
takes place over a large
area, usually under mountains
and results in high-grade
metamorphism.
II. Agents of Metamorphism
A. Heat (magma or lava)- allows the minerals
to move around and recrystallize.
B. Pressure (Stress) –
squeezes the rock
changing the density
and alignment(pattern).
How would the density
change after metamorphism?
III. Classification of Metamorphic Rocks
A. Foliated Metamorphic Rocks (pattern) minerals have aligned and show a pattern
either mineral alignment or banding.
Slate
Gneiss
B. Nonfoliated Metamorphic Rocks –
- does not show a pattern.
- has a frosted appearance
Quartzite
Marble
The comments section
gives a accurate
description of the rock
and it’s parent rock
The type of
metamorphism section
tells you how the rock was
created
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3.4 Metamorphic Rocks