Transcript Metamorphic Rocks

Metamorphic Rocks
https://www.youtube.com/watch?v
=2g-v-u5O3Xc
http://www.youtube.com/watch?v=
1oQ1J0w3x0o
Formation
Deep within the Earth heat and
pressure alter a parent rock without
melting it
“Recrystallization”
Regional Metamorphism
Caused by extreme pressure
and heat.
Happens over wide “regions”.
Mountain building, plate
tectonic forces
Contact Metamorphism
Molten rock, extremely hot,
comes into contact with
older surrounding rocks
Texture
Refers to whether or not the
component minerals are arranged in
any irregular, repeated parallel pattern
a. Foliated
Repeated layer-like appearance due to
parallel alignment of flat or long grains
i. Mineral alignment – parallel alignment
of minerals
ii. Banded – alternate between light and
dark wavy stripes
Distorted Structure
Types of Foliation: Banded
Gneissic Foliation- minerals are
squished into bands – alternate
light and dark wavy stripes
“Zebra Stripes”
Banding vs. Layers
Banding
Layers –
Sedimentary Rock
ONLY
Schistose foliationminerals have been squashed
into flakes of mica.
Slaty foliationRock splits into flat, thin
layers.
b. Non-foliated
Composed of interconnected mineral crystals
Distinguish by mineral content
Quartzite
Marble
HOW DO YOU KNOW IT’S A
METAMORPHIC ROCK?
it has:
1. Foliation
2. Banding
Take out your Handy Dandy Earth
Science Reference Tables Page 7.
Slate
+
+
=
Phyllite
Phyllite
+
+
=
Schist
Schist +
+
=
Gneiss
Rock Cycle
Natural process in which rocks change
from one rock type into another rock
type over time
ESRT Page 6