1. Formation of Sedimentary Rocks

2. 1. What is sediment?
Sediments are pieces of solid material that have been deposited on Earth’s surface by wind, water, ice, gravity, or chemical precipitation.
When sediments become cemented together, they form sedimentary rocks.

3. 2. Weathering
Step 1
Earth’s surface is subject to weathering, a set of physical and chemical processes that break rocks.
During physical weathering, rocks break into smaller pieces.

4. 2. Weathering
Chemical weathering occurs when minerals in a rock are dissolved or chemically change.
During chemical weathering, less-stable minerals break down and stable minerals get smaller.

5. Step 2 3. Erosion and Transport
After weathering, rock fragments are transported to different locations.
The removal and movement of surface material from one place to another is called erosion.
There are 4 main agents of erosion: wind, water, gravity and glaciers.

6. 3. Erosion and Transport

7. 3. Erosion and Transport

8. Bill Nye video

9. 4. Deposition
Step 3
Deposition occurs when sediments are laid down on the ground or sink to the bottom of water bodies.
Particles settle in layers. Largest sediments will settle first, followed by smaller sediments. Why?
Sometimes sediments do not form layers. Glaciers move all sediments equally.

10. Great Salt Lake in Utah
contains many minerals
dissolved in it.

11. 4. Deposition

12. 5. Burial
Step 4
Most sediments eventually end up in the lowest places on Earth, called basins.
Basins can be over 8 km thick.
As more sediment is deposited, increasing pressure and temperature cause lithification.
Lithification is the physical and chemical process that transforms sediments into sedimentary rock.

13. Tucson is in a basin.

14. Step 5
6. Lithification
Lithify comes from the Greek word lithos, meaning stone.
Lithification begins with compaction. The weight of over-lying sediments forces the grains closer together, causing physical changes.

15. 6. Lithification
Sediments buried deep enough (3-4 km) experience temperatures that are high enough for cementation to occur.
Cementation occurs when mineral growth cements (glues) sediment grains together.
Calcite and Iron oxide are common cements.

16. 6. Lithification
Draw this!

17. 7. Features of Sedimentary Rocks: Bedding
Bedding – horizontal layering of sediments.
Graded bedding – When bedding becomes progressively heavier and coarser towards bottom layers.
Cross-bedding – horizontal layers that are tilted and cross each other.

18. Bedding examples: horizontal

19. Bedding examples: horizontal
Draw this!

20. Bedding examples: graded
Draw this!

21. Bedding examples: cross-bedded
Draw this!

22. 7. Features of Sedimentary Rocks: Fossils
Fossils – the preserved remains, impressions, or other evidence of once-living organisms.
When an organism dies, it may be buried before it decomposes. If remains are undisturbed, it might become preserved as a fossil.

23. 7. Features of Sedimentary Rocks: Fossils
During lithification, all or parts of the organism can be replaced with minerals and turn into rock.

24. 8. Classification of Sedimentary Rocks
Clastic sedimentary rocks are composed of weathered bits of rocks and minerals. - Examples: Shale (most abundant), Sandstone, Conglomerate
Chemical sedimentary rocks form when dissolved substances separate from water.
- Examples include: limestone and coal

25. 8. Common Sedimentary Rocks Sandstone

26. Conglomerate

27. Shale with Plant Fossils

28. Limestone

29. Fossiliferous Limestone = Coquina

30. Classification of Sedimentary Rocks
Use texture and composition to identify

31. Sedimentary Rock Classification chart
Texture
(grain size)
Parent Sediment
Rock Name
Coarse, rounded
Coarse, angular
Medium
Fine
Very fine
Gravel
Conglomerate
Gravel
Breccia
Sand
Sandstone
Mud
Siltstone
Mud
Shale

32. Chemical Sedimentary rock classification chart
Composition
Texture
Rock Name
Calcite
Altered plant matter
Fine to coarse crystalline
Limestone
Various sized shells and shell fragments, loosely cemented together
Coquina
Fine-grained organic matter
Coal

33. Add these notes to your table of contents
Add these notes to your table of contents! Introduction to Sedimentary Rocks

34. Sedimentary Rocks Mini-lab
Look at the samples at lab and fill in the table using your Sedimentary Rock ID chart.

35. Fossils are found in only one type of rock….
Sedimentary!!

36. B. Metamorphic Rocks

37. Metamorphic Rocks Formation of Metamorphic Rocks
 Metamorphism means “to change form.”
 Most metamorphic changes occur at elevated temperatures and pressures.
 Happening below Earth’s surface!!!

38. 4.4 Metamorphic Rocks Main Agents of Metamorphism  Heat
Provides the energy needed to drive chemical reactions
 Pressure
Causes compaction and greater density

39. Metamorphic Rocks Classification of Metamorphic Rocks
 Two main categories
1. Foliated Metamorphic Rock
Has a banded or layered appearance
Example: Gneiss
2. Nonfoliated Metamorphic Rock
No banding
Examples: Quartzite, Marble

40. Foliated Metamorphic Rock Classification chart
Grain size
Comments
Parent
Rock
Rock Name
Very fine
Smooth and dull
shale
Slate
fine
Breaks along platy surfaces, glossy sheen
slate
Phyllite
Medium to coarse
Shiny minerals dominate
Schist
Banding
Schist or granite
Gneiss

41. Non-Foliated Metamorphic Rock Classification chart
Grain size
Comments
Parent
Rock
Rock Name
fine
Interlocking calcite grains
Limestone
Marble
Medium to coarse
Fused quartz grains
Sandstone
Quartzite

42. Gneiss Typically Displays a Banded Appearance

43. Marble—A Nonfoliated Metamorphic Rock