Download Metamorphic Rocks and The Rock Cycle

Guided Notes about
Metamorphic Rocks
Chapter 6, Section 3
1) Describe how and when a
metamorphic rock may form.

When high temperature and
pressure combine to alter the
texture, mineralogy, or chemical
composition of a rock without
melting it, a metamorphic rock may
form.
2) Where does the heat for
metamorphism come from?

The heat for metamorphism comes
from the Earth’s internal heat,
generated in the core, and spread
through the mantle.
3) Where does the pressure
come from?

Pressure for metamorphism comes
from vertical pressure caused by
the weight of overlying rock, or
from the compressive forces of
mountain building.
4) What are the major
differences between regional and
contact metamorphism


When high temperature and pressure
affect large regions of Earth’s crust,
they produce large belts of regional
metamorphism.
When molten rocks, such as those in an
igneous intrusion, come in contact with
solid rock, they form a local effect
called contact metamorphism.
5) What are the 2 classes of
metamorphic rock texture?

Foliated

Nonfoliated
6) What causes foliated rocks
to form?

High pressure during
metamorphism causes minerals
with flat or needle-like crystals to
form with their long axes
perpendicular to the pressure.
7) What are nonfoliated rocks
made from?

They are made from minerals
that form with blocky crystal
shapes.
8) How do porphyroblasts form,
and what is one mineral…


When new metamorphic minerals
grow very large crystals while the
surrounding minerals remain small.
Garnets are an example of
porphyroblasts.
9) What is the rock cycle?
How is it a type of recycling?


The continuous changing and remaking
of rocks caused by the internal heat and
pressure of the Earth and the processes
of erosion is called the rock cycle.
The rock cycle is a type of recycling
because the rocks of the Earth’s crust
are constantly being reformed into
different classes of rock.