Metamorphic RocksMetamorphic Rocks

Aim: How do rocks morph?Aim: How do rocks morph?

1. Metamorphic means…1. Metamorphic means…a. “a. “Meta" and “" and “Morph" means to " means to change form

b. Any rock can become b. Any rock can become metamorphic.metamorphic.

c. Living organisms undergo c. Living organisms undergo metamormetamorphosisphosis to to change form at different stages of their lives. (ex. change form at different stages of their lives. (ex. Butterflies and frogs)Butterflies and frogs)

d. Rocks undergod. Rocks undergo metamor metamorphism phism to change form to change form when different processes act upon them.when different processes act upon them.

2. Made by…2. Made by…

a. Undergoing a. Undergoing extreme heat an extreme heat an pressurepressure

b. But NOT enough to b. But NOT enough to melt back to melt back to magmamagma

3. Where do they come 3. Where do they come from?from?

a. Parent rocka. Parent rock – the original rock that was changed – the original rock that was changed

b. Metamorphic rocks are harder than the parent rockb. Metamorphic rocks are harder than the parent rock

c. Shale (sedimentary) + heat and pressure c. Shale (sedimentary) + heat and pressure Slate Slate Phyllite Phyllite Schist Schist Gneiss Gneiss

4. Locations – deep under 4. Locations – deep under continents and near magma continents and near magma

intrusions intrusions

Increasing heat and pressure near subduction zone

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5. 2 Types of formation5. 2 Types of formation

a. Contact metamorphism – rock that touches nearby magma, occurs near igneous intrusions

Magma intrusions…Magma intrusions… 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….What type of rock is….

5. 2 Types of formation5. 2 Types of formation

b. Regional metamorphism – over large areas, where crust collides or buried deep under continents

6. Categories (based on 6. Categories (based on texture of the rock)texture of the rock)

a.a. FoliatedFoliated – – minerals align in minerals align in bands, usually bands, usually containing mica, containing mica, can be fine to can be fine to coarse texturecoarse texture

b.b. Often the bands Often the bands look distortedlook distorted

Foliated Examples….Foliated Examples….

Schist - Flakes of mica

Phyllite – waxy sheen

Gneiss – obvious bands

6. Categories (based on 6. Categories (based on texture of the rock)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….Nonfoliated Examples….

ESRT Examples:ESRT Examples:

What kinds of metamorphic rock can What kinds of metamorphic rock can contain garnet?contain garnet?

How is hornfels formed and from How is hornfels formed and from what parent rock?what parent rock?

Which rock is composed of the Which rock is composed of the minerals calcite or dolomite?minerals calcite or dolomite?

What is the grain size of slate?What is the grain size of slate? What is quartzite formed from?What is quartzite formed from?

Animations of metamorphic Animations of metamorphic formationformation

http://www.classzone.com/books/earthttp://www.classzone.com/books/earth_science/terc/content/visualizations/h_science/terc/content/visualizations/es0607/es0607page01.cfm?chapter_es0607/es0607page01.cfm?chapter_no=visualizationno=visualization

http://www.harcourtschool.com/activihttp://www.harcourtschool.com/activity/science_up_close/607/deploy/interfty/science_up_close/607/deploy/interface.htmlace.html

Do NOW: MetamorphicsDo NOW: Metamorphics

Type of rock? Order of Type of rock? Order of events?events?

http://www.volcanoworld.org/vwdocs/vwlessons/lessons/Rocks/Rocks8.html

IgneousIgneous SedimentarySedimentary MetamorphicMetamorphic

Texture – Texture – intrusive or intrusive or extrusiveextrusive

Clastic – Clastic – sediments sediments compacted compacted and and cementedcemented

Foliated – Foliated – banding, banding, sometimes sometimes distorteddistorted

Intergrown Intergrown crystalscrystals

LayersLayers Shiny flakes Shiny flakes of micaof mica

Vesicular – Vesicular – gas holesgas holes

Organic – Organic – coal or coal or fossilsfossils

Nonfoliated Nonfoliated

Mafic or Mafic or felsicfelsic

Chemical – Chemical – precipitates precipitates or or evaporitesevaporites

Online practice:Online practice:

http://www.kidsgeo.com/geology-gahttp://www.kidsgeo.com/geology-games/rocks-game.phpmes/rocks-game.php