1. Sedimentary Rocks

2. Rocks can form from particles
Sediments- are materials that settle out of water or air.
Loose materials of rocks and minerals
Pieces of plant and animal remains

3. Sedimentary rocks
Develop from layers of sediment that build up on land or underwater
This sediment comes from weathering (chemical or physical)
It collects and forms layers
Deposition is when sediments are laid down on the ground or sink to the bottoms of bodies of water

4. Layers of sedimentary rock
These layers can get pressed together by the PRESSURE from the upper layers
Lithification- the physical and chemical processes that transport sediments into sedimentary rocks--- this begins with compaction

5. Layers of sedimentary rock
Sediment can also be held together by minerals that have crystallized between them, acting as a cement
Cementation- when mineral growth cements sediments together into solid rock
can either occur when a new mineral grows between the grains
OR the same mineral grows between and over the grains in a process called overgrowth.

6. Examples of sedimentary rocks
Limestone(coral reefs), coal, gypsum

7. Limestone is made of carbonate minerals

8. Coral reefs consist of limestone that comes from organisms

9. Coal is made up of dead plants

10. Conglomerate consists of individual stones that have become cemented together

11. Shale is the most common sedimentary rock and was once clay minerals

12. Features of Sedimentary Rocks
The primary feature of sedimentary rocks is horizontal layering, called bedding.

13. Graded Bedding
Bedding in which the particle sizes become progressively heavier and coarser towards the bottom layers.
Often seen in marine sedimentary rocks

14. Cross-Bedding
Formed as inclined layers of sediment move forward across a HORIZONTAL surface.
Can be observed at sandy beaches, along sandbars and dunes.

15. Fossils Best known feature of sedimentary rocks
During lithification, parts of the organism can be replaced minerals and turned into rock (like fossilized shells).

16. Clastic Sedimentary Rocks
Most common type of sedimentary rocks
Formed from deposits of loose sediments
Classified by the size of their particles
Coarse-grained
Medium-grained
Fine-grained

17. Coarse-grained Clastics
Sedimentary rocks consisting of gravel-sized rock and mineral fragments
Conglomerates and Breccias----both coarse grained but rounded edges in conglomerate indicate it had a long transport distance and was weathered and rounded

18. Medium-Grained Clastics
Medium-grained clastics- contain sand-sized rock and mineral fragments
Example: Sandstone-can be used to map old stream and river channels
Porosity- percentage of open spaces between grains in a rock

19. Fine-grained clastics
Fine-grained clastics- sedimentary rocks that contain silt and clay sized sediments and mud (siltstone and mudstone)
Example: Shale---LOW porosity

20. Chemical Sedimentary Rocks
Rocks Formed From Evaporation
When concentrations of dissolved minerals reaches saturation (the point at which no more minerals can be dissolved in the water), crystal grains precipitate out of solution and settle at the bottom. The layers of sedimentary rocks that from as a result of his are called evaporites.

21. Most Common Evaporite Minerals
Calcite (CaCO3), Halite (NaCl) and Gypsum (CaSO4)

22. Organic Sedimentary Rocks
Formed from the remains of once-living things
Examples: Limestone (mostly calcite), coral, limestone (from shells etc.), coal
Sedimentary rocks provide geologist with information about surface conditions that existed in Earth’s past