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Metamorphic Rocks
2006 Prentice Hall Science Explorer- Earth Science
Liz LaRosa http://www.middleschoolscience.com 2009
Images from Geology.com unless otherwise noted

Metamorphic comes from the Greek word meta, meaning
“change” and morphosis meaning “form”.

Heat and pressure deep beneath Earth’s surface can
change any rock into metamorphic rock.

When rock change into metamorphic roc, its appearance,
texture, crystal structure, and mineral content change.

Metamorphic rock can form out of igneous, sedimentary,
or other metamorphic rock.

Sometimes forces inside Earth can push
the rock down toward heat in the mantle.
Pockets of magma rising through the crust
also provide heat that can produce
metamorphic rocks.
The deeper a rock is buried, the greater the
pressure many times greater than the Earth’s
surface, the minerals in a rock can be
changed into other minerals.
http://www.fi.edu/fellows/payton/rocks/create/metamorph.htm

Geologists classify metamorphic rocks according to
the arrangement of the grains that make up the
rocks.

Foliated- metamorphic rocks that have their grains
arranged in parallel layers of bands. Ex- slate, schist,
and gneiss.

Non-foliated- metamorphic rocks that have mineral
grains arranged randomly.
Ex- marble, quartzite

Foliated - contain aligned grains of flat
minerals in parallel layers or bands
Gneiss is foliated
metamorphic rock
that has a banded
appearance and is
made up of granular
mineral grains.
It typically contains
abundant quartz or
feldspar minerals.

Non-Foliated – mineral grains are not
arranged in plains or bands, just random.
Marble is a nonfoliated metamorphic
rock that is produced
from the
metamorphism of
limestone.
It is composed
primarily of calcium
carbonate.

Determine if the following rock samples are
foliated or non-foliated:
Amphibolite
Quartzite
Phyllite
Foliated
Types of Metamorphism
Types of Metamorphism

Contact Metamorphism – heated by nearby magma

Increased temperature changes the composition of the
rock, minerals are changed into new minerals.
Hornfels is a fine-grained non-foliated
metamorphic rock produced by
contact metamorphism
http://www.windows.ucar.edu/tour/link=/earth/geology/meta_contact.html&edu=h igh&fr=t
Types of Metamorphism

Regional Metamorphism –
pressure builds up in rocks
that is deep within the Earth

Large pieces of the Earth’s
crust collide and the rock is
deformed and chemically
changed by heat and pressure
http://www.windows.ucar.edu/tour/link=/earth/geology/meta_regional.html&edu=high&fr=t

Marble and slate are two of the most useful metamorphic
rock.

Marble is is mostly used for building and sculpture.
Lincoln Memorial in Washington, D.C. is made of gleaming
white marble.

Slate comes in a variety of colors, including gray, black,
red, and purple. Because it is foliated, slate splits easily
into flate pieces. These pieces can be used for flooring,
roofing, outdoor walkways, chalkboards, and as trim for
stone buildings.