1. Rocks and the Rock Cycle

2. Rock Classification Rocks are classified by: How they form Texture
Grain size
Mineral composition
Conglomerate Sedimentary Rock

3. Three Types of Rocks
Igneous
Sedimentary
Metamorphic
Schist

4. Igneous Rocks Hard and Durable Uses – building material
Igneous rock: forms when molten rock (magma) cools and hardens
Classified by:
Where they form
Crystal (grain) size
Hard and Durable
Uses – building material
Basalt

5. Intrusive Igneous Rock
Intrusive igneous: cooling takes place slowly beneath Earth’s surface (magma hardened beneath the surface of the Earth)
Forms coarse grained rocks with large crystals
Ex: granite, pegmatite
granite

6. Extrusive Igneous Rock
Extrusive igneous: cooling takes place rapidly on Earth’s surface (lava that erupted onto Earth’s surface)
Forms fine grained rocks with small or no crystals; glassy texture
Ex: basalt, rhyolite
Pumice

7. Sedimentary Rock
Sedimentary rock: forms from the compaction and/or cementation of sediments
This process is called lithification
Sediments are:
Rock pieces
Mineral grains
Shell fragments
Limestone

8. How do sediments form?
weathering
Sediments form through the processes of weathering and erosion of rocks exposed at Earth’s surface
erosion

9. Sedimentary Rock con’t….
Sedimentary rock can also form from the chemical depositing of materials that were once dissolved in water
When water evaporates, minerals left behind form rock
gypsum
Ex: shale, sandstone
Uses: tools and building materials

10. Metamorphic Rock
Metamorphic rock: forms when any rock type is changed into a different kind of rock
Changes due to great heat and/or pressure
Uses: statues and buildings
Gneiss

11. Metamorphic Cont. Foliated – describes thin, flat layering
Ex: slate, gneiss
Nonfoliated – grains arranged randomly
Ex: marble

12. How does rock change?
Rocks are heated, squeezed, folded, or chemically changed by contact with hot fluids
The deeper the rock is buried, the higher the pressure on the rock
marble

13. The Earth Recycles Rock
The rock cycle is an ongoing series of processes inside Earth and on the surface
Slowly changes rocks from one kind to another
Any type of rock can change into another type

16. Rocks Foldable Three tabs: Type of rock How they form
At least 2 examples

17. Rock Cycle Poster
Draw a colorful diagram of the rock cycle; make sure to include:
3 types of rocks
Erosion and weathering
Sediments
Compaction and cementation
Magma
Melting
Heat and pressure

18. Test Your Skills
Bed Based on the processes shown in the diagram, which type of rock is formed at #1?
A.              A. Sedimentary
B.              B. Igneous
C.              C. Metamorphic
D.              D. Clastic
Because heat and pressure are needed to form #3, it must be what type of rock?
A.     Sedimentary
B.     Igneous
C.     Metamorphic
D.     Clastic

19. Cementation and compaction (lithification)
Heat and pressure
Weathering, transportation(erosion), and deposition
Cooling and solidification
Melting