1. The Rock Cycle

2. Rock Cycle The Rock Cycle is:
A process in which a rock is able to change into other types of rocks.
Types include:
Igneous
Sedimentary
Metamorphic

3. Where are rocks found? EVERYWHERE!!!! On top of Mountains
Under Mountains
Volcanoes
Rivers
Lakes

4. Igneous Rocks Igneous means: From Fire
Form from the cooling of magma or lava.
Magma is inside the Earth
Lava is outside the Earth

5. How are Igneous Rocks Classified?
They are classified by their texture and composition.
Texture can be coarse-grained or fine-grained.
Coarse-grained
Feels Rough
Has Crystals
Fine-grained
Feels Smoother
Has little or no crystals

6. Coarse-Grained Has crystals because the rock cooled SLOWLY
Coarse-grained rocks are also known as INTRUSIVE because they cooled inside the Earth from MAGMA.

7. Fine-Grained
Has no crystals because the rock cooled QUICKLY (or fast).
Known as EXTRUSIVE because they form on the surface of the Earth from LAVA.

8. Composition Two types of composition: Felsic Minerals Mafic Felsic
Made out of dark minerals
Felsic
Made out of light minerals
Mafic Minerals

9. What type of Igneous Rock is this?????
Intrusive or Extrusive?
Intrusive or Extrusive?
Felsic or Mafic?

10. Sedimentary Rocks
Sediment – Broken pieces of rock Sedimentary Rock – A rock made out of sediment

11. Sedimentary Rocks Steps of Sedimentary Rock Formation Weathering
Erosion
Deposition
Compaction
Cementation
Sedimentation

12. Sedimentary Rocks
Weathering – The mechanical or chemical processes that cause exposed rock to break into sediment.
Mechanical Weathering – Rock is broken down by physical types of weather
Chemical Weathering – Rock goes through chemical changes, that break down the rock

13. Mechanical Weathering
Temperature
High Temperature causes water in rocks or soil to evaporate, creating cracks in the ground.
Low Temperature causes rocks to contract during the winter, then during the spring and summer the rock expands, causing it to crack.

14. Mechanical Weathering
Frost Weathering
Temperature drops below freezing
Water inside of a rock freezes
Water expands when it freezes
Expansion pushes sides of rock apart
During Spring, ice melts.

15. Mechanical Weathering
Abrasion
Water crashes against the rock
Over time the rock becomes sand on a beach
Wind hits the rock repeatedly
Over time the rock becomes sand in a dune

16. Mechanical Weathering
Biological – Plants or animals break rock down
Plant
Roots from a tree force rock to break and the root goes into the cracks.
Lichen or Moss attach to the rock and break it down into dirt.

17. Chemical Weathering
Breaks down rock and changes the composition of the rock
Acidification
Rock dissolves from exposure to acid in water
Oxidation
Iron in rocks combine with Oxygen and cause rock to form rust (red)

18. Erosion Erosion – moves sediment by wind or water and gravity Water
Rain
Rivers
Glaciers
Waves
Flooding

19. Erosion
Wind – carries small pieces of sediment and drops them somewhere else
Gravity – pulls down sediment towards the Earth.
Rock Slides

20. Weathering and Erosion

21. Deposition The build up of sediment
Sediment being carried in wind or water, eventually drops out of the wind or water and settles onto the ground.
Happens at the bottom of lakes or in sand dunes, etc.

22. Compaction and Cementation
Compaction squeezes sediment together
As sediment is squeezed, some of the minerals become liquid, creating mineral glue
Cementation glues sediment together

23. How are Sedimentary Rocks Classified?
Texture: Sediment comes in all shapes and sizes. Size and shape can help determine the environment in which the rock formed.
Clay and Silt < 1/16 mm (Cannot see with unaided eye)
Sand 1/16 mm to 2 mm
Gravel > 2 mm
Composition: The minerals the rock is made out of. Limestone is made out of Calcite, which reacts with acid. Other rocks can also have fossils, which also react with acid.

24. Texture

25. Composition

26. Metamorphic Rock Metamorphic – Means Change Shape
Formed by heat and pressure, NO MELTING!!!
Types of Metamorphism
Contact
Regional

27. Contact Metamorphism
Over millions of years rocks are pushed further and further underground
Magma intrusions cut through rock layers
Rocks near the intrusions are exposed to heat and pressure
Minerals rearrange/recombine to form new minerals
Mineral grains are flattened by pressure

28. Contact Metamorphism

29. Regional Metamorphism
Metamorphism occurs over a large area
Rocks changed by heat and pressure
Rocks closer to plate boundaries have the most heat and pressure

30. Foliated vs. Non-foliated
Foliated – sheet-like layering caused by shearing or differential pressure (higher pressure from one direction)
Non-foliated – no layering, rocks under heat and pressure, but there is no shearing or not enough pressure in one direction