1. Rocks

2. Classifying rocks Rocks are made up of two or more minerals.
About 20 minerals make up most of the earth’s rocks.
When studying rocks, geologists observe the mineral composition, color and texture of the rock.
This rock contains
three minerals.

3. Rock color
A rock’s color can indicate the rock’s mineral composition. Certain minerals are light in color while other minerals are dark in color.
Granites are usually light
Basalts are usually dark

4. Rock Texture Texture involves 3 components: Grain size Grain shape
Coarse grained
Texture involves 3 components:
Grain size
Grain shape
Grain pattern
Fine grained
Jagged grains
Rounded grains
banded
Nonbanded

5. Three Groups of Rocks Igneous – form from the cooling of magma or lava
Sedimentary – form when particles of rocks are pressed & cemented together
Metamorphic – when existing rocks are changed by heat, pressure, or chemical reactions.

6. This is NOT the correct answer!

7. How do Igneous Rocks Form? First rocks must melt into Lava/Magma!
Increase in Temperature – rocks melt
Decrease in Pressure – hot rock can remain solid if it is under high pressure deep within the Earth. When hot rock rises to the surface, the pressure goes down and rocks can melt.
Addition of Fluids – when fluids, such as water, mix with rock, the melting temperature of the rock decreases and the rock can melt.

8. IGNEOUS ROCKS Granite Basalt Most common Intrusive rock
Igneous rocks are classified according to their origin, texture, and mineral composition.
ORIGIN:
Extrusive – formed from lava that has erupted (outside-”exit”).
Intrusive – formed when magma hardens under the earth’s surface (inside).
Most common
Extrusive rock
Basalt
Most common
Intrusive rock
Granite

9. Types of Magma/Lava
Different compositions of lava or magma determine the types of igneous rocks formed.
Magma that contains sodium, potassium, and aluminum will form light colored called Felsic rocks such as granite.
If the magma is high in iron, magnesium and calcium will form dark colored rocks called Mafic such as basalt.

10. Extrusive vs. Intrusive
Rapid cooling
Small crystal size; fine grained
Can have a glassy texture
Intrusive
Slow cooling
Larger crystals; coarse grained

11. Uses of Igneous Rock
Igneous rock has been used for thousands of years for buildings and statues. Granite is the most widely used igneous rock.

12. Borax Experiment Final Observations
Trace two petri dish circles into your notebook.
Inside one circle draw what you see with the unaided eye.
Inside the second circle, draw what you see with the magnifying glass.
Describe the process we used to create these crystals.
How do these crystals compare with igneous rock creation?

13. SEDIMENTARY ROCKS
Sediments are small bits & pieces of rocks, shells, sand, bones, or parts of plants.
This is
called silt
Can you see
the shells?
Sediments can be carried
away by water to be
deposited somewhere else.

14. From Sediment to Rock Step 3 Step 4 Steps 1 & 2 Erosion Cementation
Particles are carried away by wind or water
Particles are deposited
DEPOSITION
Erosion
Particles are squeezed together by pressure
Compaction
Particles are glued together as mineral solutions harden
Cementation
Step 3
Step 4
Steps 1 & 2

15. Sedimentary rock formation

17. Formation under water The most noticeable feature of sedimentary rocks are layers called strata. Stratification is the process in which sedimentary rocks are arranged in layers.

18. Three Major Types of Sedimentary Rocks
Clastic
Rock formed by rock fragments that are cemented together; sometimes visible large fragments, sometimes small, fine fragments
Two common types are conglomerates, sandstone, breccias
Organic
Rocks formed by the remains of plants/animals that are cemented together.
Two common types are coal and limestone
Chemical
Formed when minerals dissolved in water are crystallized when the water evaporates away
Calcite and Halite can form this way.

19. CLASTIC SEDIMENTARY ROCKS
This is a breccia.
Notice the jagged
edges.
This is sandstone.
The individual fragments
Are not easily seen.
These are conglomerates
This is shale, splits
easily into thin sheets.

20. ORGANIC SEDIMENTARY ROCKS
Limestone – forms in the ocean from shells, corals, calcite skeletons being compacted
Coquina- a special type of limestone
In which shells can be easily seen
Coal is one of the most
important organic rocks.
Fossils are found mainly
In sedimentary rocks.

21. The formation of COAL

22. Coal is made from once living plants & animals.

23. Limestone is formed from corals, and other sea animals.
These shells and animal remains get crushed and cemented together over time to form limestone.

24. Limestone formations These are located in Vietnam.
These are called pancake rocks!

25. More limestone formations
Many cave formations are made of limestone.
Here are some hot springs in limestone.

26. Chemical Sedimentary Rocks
Gypsum and Halite are two of the most common chemical sedimentary rocks.
They can also be minerals!
They formed by dissolved chemicals crystallizing as water evaporates.
For this reason they are sometimes called EVAPORITES.

27. This is a chemical form of limestone. It is called TUFA.
This is GYPSUM in a cave in
New Mexico. Gypsum is
Calcium Sulfate. It is used
In plaster of paris, drywall,
and Cement.
This is a chemical form of limestone. It is called TUFA.

28. Coral Reefs are responsible for much of the limestone on earth.
Coral is an animal much like a sea anenome. They have tentacles and eat plankton. To protect their soft bodies they secrete a hard substance called CALCITE. When they die, these calcite shells remain.

29. Ancient Coral Reef vs. Living Coral Reef
Great Barrier Reef
Australia

30. Sedimentary Rock Experiment
What are some similarities between the three samples?
What are some of the differences?
Are the grain sizes in the samples the same?
How would you describe the shapes of the grains you observe?

31. Sedimentary Rock Experiment
Closure
Draw a cycle, cartoon or some animation of your understanding of the formation of sedimentary rocks. Color your drawing if time permits.
Draw and label the layering of the sediments after they settle.

32. METAMORPHIC ROCKS
Heat (temps between degrees celcuis) & pressure deep in the earth can change any rock into a metamorphic rock. They can form from igneous, sedimentary and other metamorphic rocks.
Extremely high temps and pressures deep in the earth can actually change a rocks mineral composition.

33. Stories in Stone - Metamorphic
Form 20 red and 20 blue small marble sized spheres.
Form the yellow clay into a pancake about the size of your hand.
Break the green in half and form 2 pancakes.

34. Metamorphic Rock Experiment
Observe and describe the layering in the piece of the model you just cut off.
How was your fist similar to what happens when metamorphic rock is formed?
How was your fist different?
How is the piece of the model you “metamorphized” different from the piece you cut of that wasn’t “metamorphized”?
Describe the metamorphic layers.
How do metamorphic rocks differ from igneous or sedimentary rocks?

35. Two Types (textures) of Metamorphic Rocks
FOLIATED
Rocks grains are
arranged in parallel
bands or layers
Common examples:
Slate, gneiss, schist
NONFOLIATED
Grains are arranged
randomly.
Common examples:
Marble, quartzite

38. Non-foliated Metamorphic Rocks
qUARTZITE
MARBLE

39. With pressure, granite becomes gneiss (foliated rock)
With pressure, granite becomes gneiss (foliated rock). Igneous rock is changed to a metamorphic rock.

40. Increasing pressure causes greater foliation

41. SHALE
SLATE
SCHIST
GNEISS
SEDIMENTARY ROCK

42. Index Minerals
Some minerals, such as quartz, can form at many different temperatures.
Other minerals, such as garnet, form only at certain temperatures and pressures.
Therefore, rocks that contain minerals like garnet probably also formed at those temperatures and pressures and are called index minerals.
Index minerals and can indicate the temperature and pressure or depth at which a rock formed.

43. Two ways rock can go through Metamorphism
Regional metamorphism – high pressures and temperatures cause the rock in a large area to change. It can happen where rock is buried deep below the surface or at convergent boundaries.

44. Two ways rock can go through Metamorphism
Contact metamorphism – rock is heated by nearby magma. The nearer the rock is to the magma, the more changes occur.

45. USES OF METAMORPHIC ROCK
All MARBLE

46. World’s Largest Marble Quarry Tate, GA

47. Uses of SLATE

48. The Rock Cycle

49. Rock Cycle Simulation Where did you spend the most time?
Why is the rock cycle called a cycle?
Why did everyone not follow the same path?
How does a rock become Igneous? Sedimentary? Metamorphic?
Where are rocks being born and transformed today?

50. Rock Cycle Simulation
Where are rocks being born and transformed today?
How much of the rock cycle can be observed? How much must be inferred?
How are people affected by movement of Earth material through the rock cycle?
If each step of our rock cycle game was 200,000 years, what was the time period represented in the game?

51. The Rock Cycle
It is a series of processes in the earth’s crust, mantle and on the earth’s surface that SLOWLY change rocks from one kind to another. Click on the link for a Rock Cycle animation