1. Metamorphic Rocks
Sire Kassama
2014

2. Intro to Info
Metamorphic Rocks: Rocks created through intense heat or pressure
Are good examples of metamorphic rock: gneiss, schist, slate, marble
Alps and Himalayas are primarily composed of metamorphic rocks
Foliated metamorphic rocks are rocks that have bands of minerals in it

3. Deep within the earth; lithosphere; or subduction zone
Metamorphism
Describe the only location that provides the intense and extreme heat and pressure re-quired to form metamorphic rocks.
Deep within the earth; lithosphere; or subduction zone

4. Contact vs. Regional Metamorphism
Local or Contact Metamorphism: rocks touched by red hot magma in crust; whenever magma rises to crust
Regional Metamorphism: deep in crust from enormous pressure over a large area; two tectonic plates move toward each other; Lewissian gneiss is a good example

5. VS. Contact Regional Both occurs adjacent to igneous intrusions
Contact may result from tectonic forces resulting in compressional stresses
usually results in foliated metamorphic rocks
mineral crystals are rearranged
results in folds or curves
large crystals are formed
minerals crystallize

6. Identifying Metamorphic Rocks
Color
Foliated
Grain Size
Shale
Dark gray
Yes
Fine
Schist
Mixture No
Medium
Gneiss
Pink or gray
Coarse
Marble
Light
Quartzite

9. Need To Know on Rocks ROCK NAME
TYPE ( Igneous, Sedimentary, metamorphic)
FORMATION
Igneous (Extrusive, Intrusive) (volcanic, plutonic) (felsic or mafic)
Sedimentary ( Clastic, chemical, biochemical, organic)
Metamorphic (Regional, Contact Metamorphism) (low grade-high grade)
ENVIRONMENT
TEXTURE
Igneous (phaneritic, aphanitic, porphyritic)
Sedimentary (grain size)
Metamorphic Foliated or non-foliated
HARDNESS RANGE
MINERALS
PHYSICAL DESCRIPTION
(Color)
USES
OTHER PROPERTIES

10. Base your answers to this question on the pictures of four rocks shown below. Magnified views of the rocks are shown in the circles. What do all four rock samples have in common?
1.They show cleavage.
2. They contain minerals.
3. They are organically formed.
4. They formed on Earth’s surface.

11. Base your answers to this question on the pictures of four rocks shown below. Magnified views of the rocks are shown in the circles. Which rock is metamorphic and shows evidence of foliation?

12. Which sample best shows the physical properties normally associated with regional metamorphism?

13. Examples of Metamorphic Rocks

14. Marble Reacts with HCl and therefore contains the mineral calcite
Formed by metamorphism of limestone
Minerals: Calcite
Has no foliation
Red, white, yellow, green
Found in US, Italy, Canada, Spain, Greece
Used in sculptures, Lincoln memorial

15. Slate
Fine grained rock formed when shale, mudstone, clay, or volcanic ash is put under high pressure
Splits into thin sheets easily
Almost completely waterproof
Used for roof and floor tile, monuments, and name plates
Minerals: mica, feldspar, and quartz

16. Schist
Medium grained
Made from shale, clay, slate, and many other rocks
Put under very high temperatures and pressures
Minerals: feldspar, mica, quartz
Good for building materials
Also crushed into gravel to use for pavements

17. Gneiss
Formed at very high temperatures and pressure from different igneous and sedimentary rocks
Coarse grained and has bands of minerals that are often bent and folded
Formerly granite before exposed to immense pressure
Used to replace granite
Common metamorphic rock
Found in Sweden

18. Quartzite Formed when sandstone is heated
Formed when tectonic plates grind together
Some of the oldestest rocks made of quartzite

19. Other Resources
The following questions and answers are from the New York State Regents Website:
Geology.com

20. Contact metamorphism: alteration of rock by heat adjacent to hot lava; important setting fir metallic ores such as gold, silver, copper, zinc, lead, etc
Regional metamorphism: alteration of rock over large area by het and pressure due to deep burial or tectonic process
Metamorphic Rocks are either foliated or nonfoliated
Foliated: laminated structure in rock resulting from parallel alignment of sheet like minerals ( slate, phyllite, schist, gneiss)
Nonfoliated: no preferred orientation (marble , quartzite)