1. Bell Ringer
Igneous rocks are classified by their ________ composition and their ________ size. If you were given a rock high in silica and with small grains, you could conclude that it was [ felsic / mafic ] and [ intrusive / extrusive ].
Quiz TOMORROW ( )
(Chemistry – Rock Cycle)
Chemical/mineral
grain

2. Sedimentary & Metamorphic Rocks

3. Part 1: Sedimentary Rocks

4. Making Rocks into Sediments
Clastic Sediments – small pieces of broken-down rocks (clastic = “broken”)

5. Making Rocks into Sediments
These sediments can be cemented together into sedimentary rocks
Sedimentary rocks are the most common rocks along Earth’s surface

6. Making Rocks into Sediments
Weathering – the breaking down of rocks into sediment
Erosion – the transport of sediment from one place to another (via wind, water, glaciers, or gravity)
Deposition – the depositing (dropping, settling) of sediment in one location E W D

7. Making Sediments into Sedimentary Rocks
Lithification – the process of changing sediments into sedimentary rocks L E W D

8. 3 Steps to Lithification
Burial – new layers of sediment fall on older layers
Compaction – the weight of the new layers on top presses down the older, bottom layers
Cementation – substances begin to fill in the spaces between the sediments, cementing them together

9. Making Sediments into Sedimentary Rocks

10. Features of Sedimentary Rocks
Bedding – horizontal layering
Cross bedding – inclined layers formed as sediment spills over a surface

11. Features of Sedimentary Rocks
Graded bedding – when sediment sizes become progressively larger towards the bottom layers
Often found in marine sedimentary rocks deposited by underwater landslides. As the sliding stops, the largest/heaviest sediments settle first, followed by progressively smaller particles

12. Features of Sedimentary Rocks
Fossils – preserved examples of past life, only found in sedimentary rocks
Why not igneous or metamorphic?

13. Classification of Sedimentary Rocks
3 Main Types:
Clastic – result from the lithification of sediments
Most common type of sedimentary rock

14. Classification of Sedimentary Rocks
Sub-classified by particle size:
Coarse-grained – large (gravel-sized) sediments
Ex: conglomerate
Medium-grained – medium (sand-sized) sediments
Ex: sandstone
Fine-grained – small (silt and clay-sized) sediments
Ex: shale

15. Classification of Sedimentary Rocks
Chemical – result from evaporation of precipitate crystals (evaporites)
Most commonly found in arid (dry) regions and in oceans and drainage basins with low water flow
Examples: rock salt, gypsum

16. Classification of Sedimentary Rocks
Organic – form from the remains of living organisms
Examples: limestone, coal

17. Uses of Sedimentary Rocks
Source of fossil fuels (coal, natural gas, oil)
Source of uraninite (ore that contains uranium, used in nuclear energy)
Building materials (ex: limestone, sandstone, phosphate)

18. Part 2: Metamorphic Rocks

19. Metamorphic Rocks
Metamorphic rocks – formed when increased temperature and pressure changes rocks without melting them
The name comes from the Greek words “meta” (change) and “morphe” (form)
Metamorphism causes rocks to change texture, mineralogy, and/or chemical composition
Any type of rock (igneous, sedimentary, or even other metamorphic rocks) can undergo metamorphosis and become a metamorphic rock

20. Example: limestone (sedimentary rock) turns into marble (metamorphic rock)

21. Metamorphic Rocks
The high temperatures needed for metamorphism can happen in two ways:
When rocks get buried deep inside the Earth
When rocks near Earth’s surface come in contact with rising magma

22. Metamorphic Rocks
The high pressures needed for metamorphism can happen in two ways:
Vertical pressure caused by the weight over overlying rock
Collision of large pieces of rock during mountain-formation

23. Different temperature/pressure combinations produce different types of metamorphic rocks

24. 3 Types of Metamorphism
Regional metamorphism – when high temperatures and pressures affect large areas deep within Earth’s crust, creating large belts of metamorphic rocks

25. 3 Types of Metamorphism
Contact metamorphism – when a small pool of magma below Earth’s surface comes in contact with surrounding rocks and causes them to undergo metamorphism
Affects smaller areas (ex: areas under volcanoes) than regional metamorphism

26. 3 Types of Metamorphism

27. 3 Types of Metamorphism
Hydrothermal metamorphism – when very hot water reacts with rock and alters its chemistry and mineralogy
Can dissolve minerals, break them down, and/or deposit new minerals
Occurs in mid-ocean ridges and around volcanoes

28. Classification of Metamorphic Rocks
Two main types:
Foliated – have layers or bands of minerals
High pressure causes minerals with flat crystals to form with their long axes perpendicular to the pressure
Examples: gneiss (from granite), schist (from shale)

29. Classification of Metamorphic Rocks
Non-foliated – lack distinct layers because minerals have blocky shapes
Examples: quartzite (from sandstone), marble (from limestone)
Foliated Gneiss
Non-foliated Quartzite

30. Part 3: Bringing it all Together
The Rock Cycle

31. Rock Cycle
The rock cycle is a cycle…no matter is created or destroyed, just recycled
Any type of rock can turn into any type of rock!

33. Rock Cycle BYOD Use the website to answer the questions
ALL the information you need to answer the questions is on the website
Put in basket when complete
Study for quiz

34. Finish Igneous Rock lab.
When done, clean materials up and study for quiz (mandatory)