1. Learning Log What are the three types of rock, as defined by how they’re formed? Give an example of each type. Essential Question What are the different types of rocks? Earth Day Info Solutions for helping the Earth and ourselves

2. Sedimentary Rocks

3. Noticeable Characteristics of a Sedimentary Rock?
Often have layers or bands across them.
Often contain fossils which are fragments of animals or plants preserved within the rock.
Scrape and often crumble easily

4. Sedimentary Rocks
Much of Earth’s surface is covered with sediments – pieces of solid material deposited on Earth’s surface by wind, water, ice, gravity, or chemical precipitation
Sediments formed through weathering (breakdown of rocks)
When sediments become cemented together, they form sedimentary rocks (form in layers)

5. The formation of Sedimentary Rocks

6. Weathering
Weathering –physical and chemical processes that break rock into smaller pieces.
Chemical weathering – minerals in a rock are dissolved or chemically changed (rock changes)
Physical weathering – minerals are not chemically changed, rock fragments simply break off the solid rock (rock does not change)

7. Weathering Water: dissolves minerals
Chemical Weathering caused by
Physical Weathering caused by
Water: dissolves minerals
Oxygen: oxygen reacts with substances (oxidation)
Carbon dioxide: forms carbonic acid that dissolves minerals
Acid precipitation: changes pH of water
Temperature: influences rate of chemical reactions
Temperature: water expands as it freezes, breaking rocks open
Ex. Formation of pot holes in roads
Pressure: removing rocks above decreases pressure and allows layers to peel off
Ex. Rock removal can decrease pressure, causing large pieces of rock to explode off walls, burying miners.

8. Climate vs. Weathering Climate affects weathering
Temperature and Precipitation have greatest effect on weathering
Chemical weathering occurs more in areas with warm temperatures, high rainfall, and lush vegetation
Physical weathering occurs more in cool, dry areas, especially where repeated freezing/thawing occur
Little/no chemical weathering occurs in areas that are frigid all year round

9. Weathering Continued Rock Type and Surface Area
Topography and other variables
Weathering depends on rock’s hardness and resistance to weathering
Sedimentary rocks are more easily weathered
Mechanical (physical) weathering breaks rocks up into smaller pieces increasing surface area
More surface area equals more weathering
Rocks on slopes more likely to move, exposing underlying rocks to more weathering
Organic matter and plant roots release carbon dioxide

10. What is Erosion?
Erosion is the removal and movement of surface material (sediments) from one location to another location.
Four Main Agents: Water, Wind, Gravity, and Glaciers
Eroded materials are always carried downhill
Streams and rivers carry the small bits towards the sea (continually wearing down as they progress).
Erosion and transport:
Water- more power to move large particles than wind
Wind- moves fine, dry particles easily
Ice- carry huge boulders and piles of debris
Gravity- pulls materials downslope (down hill sides and downstream); landslides, mudflows, avalanches

11. What is Deposition?
When sediments are laid down on the ground or sink to the bottoms of bodies of water.
The sediments are dropped by size. The largest sediments will drop first and the smallest will drop last.
Sediments deposited when transport stops

12. Erosion, Deposition and Landform
Water Agent:
Water going down steep slopes erodes more because the steeper the slope the faster the water moves carrying more material longer distances than wind
Creates watershed- where water and sediment empty as it works its way toward ocean
Creates river deltas and sandbars- where sediment is dumped as it flows out of river or sounds into ocean
Deltas
NC Outer Banks sandbars
NC Outer Banks sandbars

13. Erosion, Deposition and Landform
Wind Agent:
Moves dry, small particles easily in areas where there are not many plants to hold soil in place
Winds can blow fine particles uphill creating sand dunes on shorelines

14. Erosion, Deposition and Landform
Ice (Glacier Agent):
Large-scale and dramatic; scrape and gouge out large sections of landscape
Waterfalls, lakes, and various shaped sediment deposits are created

15. What is Lithification?
Lithification is the process where sediments are converted into solid rock (physical and chemical process).
Lithification is a two part process:
Compaction: where the particles are compressed together due to the weight of the overlying sediments.
As more and more sediment is deposited, the bottom layers are subjected to increasing pressure and temperature
Cementation: is where the particles are glued together.
Begins with compaction – weight of overlying sediments force sediment grains together causing physical changes
Sediments buried to 3-4 km experience high temperatures that cause cementation – mineral growth cements sediment grains together into solid rock

16. Lithification

17. From pile of sand to solid rock

18. What is bedding?
It is the horizontal layering of deposits and is the primary feature of sedimentary rock
Cross bedding in a sandstone dome

19. What is bedding?
It is the horizontal layering of deposits and is the primary feature of sedimentary rock
Two Types-that depend on the method of transport
Graded bedding- coarser, heavier particles on bottom layer
Cross bedding- inclined layers of sediment move forward across horizontal surface
Cross bedding in a sandstone dome

20. Importance of Sedimentary Rocks
Geologic “snapshot” of surface conditions in Earth’s past.
Fossils
Flow and direction of ancient rivers
Natural resources-oil, coal, and natural gas found in sedimentary rocks
Deposits of phosphate- used for fertilizer
Limestone- used to make cement; used for building

21. Rock Identification
Each of you have had the opportunity to observe at least one sample of a sedimentary rock. In the space below note all of the observations you made about it.

22. IGNEOUS ROCK

23. What are Igneous Rocks? Crystallize from molten material:
Magma – molten rock below the Earth's surface
Lava – magma that erupts onto the Earth's surface through a volcano or crack (fissure)
Nickname- “fire form rock”

24. A rock under a microscope
Magma Formation
Factors That Affect Magma Formation:
Temperature
Pressure
Water Content
Mineral Content
Three major rock types are basalt, andesite, granite
A rock under a microscope

25. Factors That Affect Magma Formation:
Temperature
The deeper you go in the Earth’s crust the hotter it gets.
Pressure
The deeper you go pressure increases.
An increase in pressure increases melting temperature.
Water Content
As the water content of the rock increases the melting temperature decreases.
Mineral Content
Different minerals melt at different temperatures.

26. Compare and Contrast Igneous Rock

27. Types of Igneous Rock Intrusive Extrusive
Fine-grained rock that cooled quickly on Earth’s surface when lava is EXTRUDED from the Earth
Intrusive
Course grained igneous rock that cooled slowly underground
When magma cools, it crystallizes= igneous rocks
If it cools quickly (on Earth’s surface), there is not enough time for large crystals to form (extrusive)
If it cools slowly (beneath Earth’s surface), there is sufficient time for large crystals to form (intrusive)

28. Intrusive or Extrusive
Extrusive Rock
Intrusive Rock

29. Classifying Igneous Rocks
Mineral Composition
Felsic- Light colored, High Silica
Mafic- Dark colored, Low Silica
Grain Size
Size of crystal grains and chemical composition are used to classify igneous rocks
Texture
Texture depends on time it takes a rock to harden (cooling rate)

30. How Rocks Melt
Minerals have different melting points, therefore not all parts of the rock melt at the same time.
Partial melting- process whereby some minerals melt at low temperatures while other minerals remain solid
As minerals melt different elements are added to the magma stew changing the composition of the magma forming different types of igneous rocks.

31. How Rocks Melt cont.
Magma cools and crystallizes in the reverse order of partial melting
First minerals to crystallize are the last to melt during partial melting.
Fractional Crystallization- process wherein different minerals form at different temperature thus changing magma
Occurs because as each group of minerals crystallizes, it removes elements from the remaining magma instead of adding new elements.

32. Andesite
Basalt
Rhyolite

33. Gabbro
Granite
Diorite

36. Useful Characteristics of Igneous Rocks
Building Material
resistant to weathering
Strength
Ore deposits- minerals that contain a useful substance
Veins
Pegmatites
Kimberlites
diamonds
Building materials (strong, resistant to weathering)
Granite – most durable igneous rocks
Ore deposits are found within igneous rocks
Gold, silver, lead, and copper found in igneous veins
Diamonds found in igneous rocks

37. Rock Identification
Each of you have had the opportunity to observe at least one sample of an igneous rock. In the space below note all of the observations you made about it.

38. Metamorphic Rock

39. What is Metamorphism?
Metamorphism is the alteration of existing rocks by either excessive heat and pressure, or through the chemical action of fluids.
During metamorphism, a rock changes form while remaining solid.
When high temperature and pressure combine to alter the texture, mineralogy, or chemical composition of a rock without melting it, a metamorphic rock forms.
During metamorphism, a rock changes form while remaining solid.
Temperature comes from Earth’s internal heat
Pressure comes from either overlying rock or compressive forces during mountain building

40. Types of Metamorphism Regional Metamorphism Contact Metamorphism
Occurs when rocks are buried deep beneath Earth’s surface and changed by increase in temperature and pressure. Covers a large area
Contact Metamorphism
Occurs when rocks are heated by contact with magma or lava. Covers a small area
Hydrothermal Metamorphism
Extremely hot water reacts with rock and alters its chemistry and mineralogy.
Common around igneous intrusions and active volcanoes
When high temperature and pressure combine to alter the texture, mineralogy, or chemical composition of a rock without melting it, a metamorphic rock forms.
During metamorphism, a rock changes form while remaining solid.
Temperature comes from Earth’s internal heat
Pressure comes from either overlying rock or compressive forces during mountain building

41. Metamorphic Rock Textures:
Foliated Texture:
Mineral crystals arranged in parallel layers or bands (flatten under pressure)
Slate 
Schist
Gneiss 
(from granite, basalt, or shale)
(from granite)
(from clay or shale)
Foliated – wavy layers and bands of minerals
Nonfoliated – lack mineral grains with long axes in one direction

42. Foliated Texture:
Slate

43. Foliated Texture:
Schist

44. Foliated Texture:
gneiss:

45. Metamorphic Rock Textures:
Nonfoliated Texture:
No bands of crystals
Don’t break in layers
Foliated – wavy layers and bands of minerals
Nonfoliated – lack mineral grains with long axes in one direction
Quartzite
Marble

46. Foliated or Nonfoliated
Two groups:
Foliated – wavy layers and bands of minerals
Nonfoliated – lack mineral grains with long axes in one direction
Nonfoliated
Foliated

47. Rock Identification
Each of you have had the opportunity to observe at least one sample of a metamorphic rock. In the space below note all of the observations you made about it.

48. The Three Rock Types Re-Cap
Sedimentary, Igneous, and Metamorphic
Grouped according to how they form:
Sedimentary rocks form from cemented sediments
Igneous rocks crystallize from magma
Metamorphic rocks form by changes in temperature and pressure to existing rock