I FORMATION OF METAMORPHIC ROCKS A metamorphic rock

I. FORMATION OF METAMORPHIC ROCKS:

A metamorphic rock is one whose original form has changed been _____

BY____ HEAT AND _______ PRESSURE

THIS ALTERATION IS CALLED RE -CRYSTALLIZATION _______

These changes are NOT caused by MELTING

If the rock melted and cooled it would be an IGNEOUS ROCK _______

1. Changes caused by RE -CRYSTALLIZATION _______ (again)

May include the creation and growth of NEW MINERAL _______ CRYSTALS

2. Rocks which are intensely Compressed _____ can also become metamorphic ______ roc

MAKING IT MORE DENSE AND RESISTANT TO WEATHERING

The growth of new minerals may cause the rock to appear BANDED

OR foliated STRIPES OF LIGHT DARK MINERALS

pressure

SCHIST SHOWS BANDING

It can also ______ DISTORT (BEND) OR _______ DESTROY ORIGINAL STRUCTURES

3. There are two types of Metamorphism: A. Regional B. Contact

A. Regional metamorphism: occurs over large areas with extreme pressures & temperatures

Photograph of regional metamorphism New York State thruway

This extreme heat and pressure is what builds MOUNTAINS

B. CONTACT METAMORPHISM

ZONE OF IS THE _____ CONTACT WHERE AN IGNEOUS INTRUSION MEETS THE EXISTING ROCK BUT _______ DOES NOT MELT IT

Contact metamorphism occurs only at the place where the magma contacts rock SHALE SANDSTONE LIMESTONE SANDSTONE IGNEOUS INTRUSION

Any kind of rock: IGNEOUS SEDIMENTARY METAMORPHIC

CAN UNDERGO RE-CRYSTALLIZATION TO FORM METAMORPHIC ROCK.

PARENT ROCK Is rock from which metamorphic rock is formed.

Limestone metamorphoses to become _________ marble

Sandstone metamorphoses to become _________ quartzite

Shale metamorphoses to become _________ slate

Granite metamorphoses to become _________ gneiss

We will not find fossils in Metamorphic rock because:

All traces of fossils have been recrystallized

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