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and/or Pressure Extreme Extreme Heat

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G O Metamorphic Rocks on the road to something new…

Regents Earth Science with Ms. Connery To metamorphose something means to

change something from one form to another How do metamorphic rocks form?

metamorphism  extreme heat  foliated  extreme  non-foliated pressure  deformation  contact  metamorphism alignment  regional

You know it’s metamorphosed if change has occurred! Metamorphism happened here because layers were originally horizontal BEFORE FOLDING AFTER DEFORMED (FOLDED) from EXTREME PRESSURE of TECTONIC PRESSURE REGIONAL METAMORPHISM APPLIED Extreme heat of igneous magma intrusion causes CONTACT METAMORPHISM

YOUNGEST SED. LAYER

OLDEST SED. LAYER Contact metamorphism A R O U N

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G O Overview of Metamorphic Rocks “REGIONAL” metamorphism • Change caused by from extreme heat and pressure

• REGIONAL metamorphism means change at a LARGE scale over LARGE area IGNEOUS

METAMORPHIC ESRTs - Regional metamorphism • NO MELTING…just rearranging and lining up the same mineral

• Grade of metamorphism depends on how long the process goes on

• Deeper with more heat & pressure & longer time  more change occurs Regional metamorphism… Rocks show an increase in foliation & deformation as metamorphism continues Foliation when the align perpendicular to the pressure being applied Which way was the pressure applied? Foliation - minerals align or “line up” perpendicular to the pressure Scheme for Metamorphic Identification Increased pressure from regional metamorphism causes foliation to progress shale

Increased pressure from regional metamorphism changes bituminous to ANTHRACITE coal

This is NOT FOLIATED - it doesn’t have mineral alignment but it’s harder than bituminous.

What’s different?

http://www.mii.org/mineral_photos_by_type.htm#meta How does the heat of contact metamorphism changes sedimentary limestone to METAMORPHIC ?

http://www.mii.org/mineral_photos_by_type.htm#meta HEAT - Contact metamorphism

1 - Existing Rock = LIMESTONE

3- Limestone changed to MARBLE at edges

2 - Diorite () intrusion at 1000s of degrees

3 - Limestone changed to MARBLE at edges 1 - Existing Rock = LIMESTONE http://geology.about.com/library/bl/images/blcontactmet.htm

HEAT - Contact metamorphism

• Extreme heat of contact of an existing rock with an igneous (magma) intrusion or lava causes some existing rock to melt and become part of the magma.

• Along the edges (contact zone) where not quite hot enough to melt the existing rock, it “changes” the rock through recrystallization (but not melting!). Let’s ID some Metamorphic Rocks! Conceptual Model: Extreme heat of Contact metamorphism