Transcript Metamorphic Rocks and Scale

Sedimentary Rocks: Review
Metamorphic Rocks
Dr. David Steer
Rock Cycle
Metamorphic Rocks
Change in composition and/or texture of a
rock
Occurs as the result of increasing pressure
and/or temperature.
Regional Metamorphism
Regional metamorphism occurs when rocks undergo
increased temperatures and pressures
Associated with the formation of mountain belts.


Rocks may be buried to great depths (10-20 km)
Temperatures in excess of 700 oC and pressures of 7 kilobars (7
million atmospheres).
Increase in grain size
Platy minerals become aligned (foliated)
At high enough grades segregation of light and dark
minerals occur (gneiss)
Regional Metamorphism
Draw a schematic picture of the process
Examples of Regional Metamorphic Rocks
Schist
Forms when mudrocks are
heated
Gneiss
Forms
when rocks
ranging from mudrocks
to granites are heated
and pressurized
Contact Metamorphism
Contact metamorphism occurs when rocks come in
contact with a heat source (usually a magma body).
Essentially the rocks are getting baked, like in an oven.
Grain size increases as the result of increased
temperature.
Grains are often randomly oriented
Contact Metamorphism
Draw a schematic picture of the process
Review
Two of these rocks are igneous, 2 are metamorphic and
one is sedimentary. Which rocks most likely metamorphic?
Temperature
A
B
C
Depth
D
E
Examples of contact metamorphic Rocks
Marble
forms when
limestone is heated
•Quartzite
forms when
sandstone is heated
Create a Concept Map
Key Words:
regional metamorphism
gneiss
magma chambers
contact metamorphism
heat
heat and pressure
mountain belts
grain size
marble
non-foliated rocks
Linking phrases:
surrounding
can be formed by
classified by
caused by increasing
that results in
such as
formed from an existing
rock like
associated with
Identify your metamorphic rocks