Transcript Metamorphic Rocks

Metamorphic Rocks
Aim: How do rocks morph?
1. Metamorphic means…
a. “Meta" and “Morph" means to change form
b. Any rock can become metamorphic.
c. Living organisms undergo metamorphosis to change form
at different stages of their lives. (ex. Butterflies and frogs)
d. Rocks undergo metamorphism to change form when
different processes act upon them.
2. Made by…
a. Undergoing extreme
heat an pressure
b. But NOT enough to
melt back to magma
3. Where do they come from?
a. Parent rock – the original rock that was changed
b. Metamorphic rocks are harder than the parent rock
c. Shale (sedimentary) + heat and pressure
 Slate  Phyllite  Schist  Gneiss
4. Locations – deep under continents
and near magma intrusions
Increasing heat and pressure from depth
Increasing heat and pressure near subduction zone
5. 2 Types of formation
a. Contact metamorphism – rock that touches
nearby magma, occurs near igneous intrusions
Magma intrusions…
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Batholith – big area of “deep rock”
Sill – magma forms parallel between rock layers
Dike – magma rises through vertical fractures
Laccolith – “lake of rock”
What type of rock is….
5. 2 Types of formation
b. Regional metamorphism –
over large areas, where
crust collides or buried
deep under continents
6. Categories (based on texture of
the rock)
a.
b.
Foliated – minerals
align in bands,
usually containing
mica, can be fine to
coarse texture
Often the bands
look distorted
Foliated Examples….
Phyllite – waxy sheen
Schist - Flakes of mica
Gneiss – obvious bands
6. Categories (based on texture of
the rock)
b. Non-foliated –
- minerals are not arranged in bands
- usually one or two minerals that grow
in size and change composition in a
process called recrystallization
Nonfoliated Examples….
ESRT Examples:
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What kinds of metamorphic rock can
contain garnet?
How is hornfels formed and from what
parent rock?
Which rock is composed of the minerals
calcite or dolomite?
What is the grain size of slate?
What is quartzite formed from?
Animations of metamorphic
formation
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http://www.classzone.com/books/earth_sc
ience/terc/content/visualizations/es0607/e
s0607page01.cfm?chapter_no=visualizatio
n
http://www.harcourtschool.com/activity/sc
ience_up_close/607/deploy/interface.html
Do NOW: Metamorphics
Type of rock? Order of events?
http://www.volcanoworld.org/vwdocs/vwlessons/lessons/Rocks/Rocks8.html
Igneous
Texture –
intrusive or
extrusive
Sedimentary
Clastic –
sediments
compacted
and cemented
Layers
Metamorphic
Foliated –
banding,
sometimes
distorted
Intergrown
Shiny flakes of
crystals
mica
Vesicular –
Organic – coal Nonfoliated
gas holes
or fossils
Mafic or felsic Chemical –
precipitates
or evaporites
Online practice:
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http://www.kidsgeo.com/geologygames/rocks-game.php