1. SEDIMENTARY ROCKS Sedimentary rocks form from various types
of sediment.
Sedimentary rocks make up 90% of SURFACE rocks and only about 1% of Earth’s crust.

2. How are Sedimentary Rocks Formed
Sedimentary rock forms when sediments are combined to form solid rock
“Lithification” is the fancy name for forming rocks.
Sedimentary rock is formed in two ways:
Compaction
Formed by pressure compacting the sediments together
AND/OR
Cementation
Pressure forces water out of the sediments, the dissolved mineral crystallize, cementing the sediments together

3. Compaction and Cementation of Clastic Sediment into Rock
“Overburden” is extra stuff on top. More sediment, a continent, whatever.
Overburden

4. Three Kinds of Sedimentary Rocks
1. Clastic – fragments of other rocks. For example: shale, sandstone, conglomerate
2. Crystalline – formed from mineral grains that fall out of solution by chemical action or evaporation. For example: Rock salt and chemical limestone.
3. Bioclastic – formed from remains of plants or animals. For example: Coal and limestone from shells (coquina).

5. How are Clastic Sedimentary Rocks formed
Sediment is deposited and then goes through the process of lithification (forming sediment into sedimentary rocks)

6. How are Clastic Sedimentary Rocks formed
Weathering
Erosion
Deposition
Lithification

7. Clastic Sedimentary Rocks
Clastic sedimentary rocks are characterized based on their grain size.

8. How are Clastic Sedimentary Rocks formed.
Grain sizes vary from Coarse (pebbles, cobbles, boulders) to Medium (sand) to Fine (silt and clay).

9. Grain Sizes Boulders Cobbles Coarse Gravel Fine Gravel
Coarse / Medium Sand
Fine Sand – Powdered Sugar
Silt - Powder

10. Mixed

11. How Does The Sediment Get Sorted Into Different Sizes?
Running water (rivers, streams, creeks) pick up sediment and carry it along its travels.
The faster the water is moving, the larger the particle that can be carried, and vice-versa.
When a river hits a larger body of water, like a lake or ocean, it’s like hitting a brick wall. This results in the river “dumping it’s load” – dropping all the sediment it’s been carrying.
The sediment gets dumped according to size!

12. How Does The Sediment Get Sorted Into Different Sizes?
The bigger sediment gets deposited FIRST, since it’s bigger, heavier and sinks first.
Then, the sediment gets gradually SMALLER the farther you go from where the river hits the lake or ocean.
Therefore, coarse clastic rocks get made where the larger sediment gets deposited and the medium to fine clastic rocks get made further away from that point.

14. Clastic Sedimentary Rocks
Conglomerate – made of pebbles and/or cobbles cemented together by sand, silt and clay. Coarse-grained
Sandstone – sand that has been cemented together. Medium-grained
Shale – made from clay. Fine-grained

16. Crystalline Sedimentary Rocks
Also called chemical sedimentary rocks.
Chemical action or evaporation causes minerals to drop out of solution.
This process creates chemical or crystalline sedimentary rocks.
For example: Calcite will precipitate out of water and build-up to form chemical limestone (it will fizz with acid since it has calcite in it!)

17. Crystalline (Chemical) Sedimentary Rocks
Gypsum Rock – made when the mineral gypsum precipitates out of water.
Chemical Limestone

18. What happens when salty water evaporates and just salt is left behind?
Bonneville Salt Flats of the Great Salt Lake, Utah. The lake bed is covered with rock salt which gives it the white color. The salt is mined by the Morton Salt Company.

20. Bioclastic (Organic) Sedimentary Rocks
Also called Organic sedimentary rocks.
Formed from once-living things like plants and animals.
For example: Plants die and decay and form coal.
Another example: Shells can get broken up and cemented back together to form organic limestone (also called coquina).

21. Bioclastic (Organic) Sedimentary Rocks
Organic Limestone or Coquina
Coal

22. Bioclastic Rock

24. Answers Define Clastic- Define bioclastic-
What type of rock is made of particle .05 cm?
What type of rock is made of particle .1 cm?
5. What is the chemical composition of bituminous coal?
Made from fragments of other rocks
Formed from remains of plants or animals
Sandstone
Sandstone
Carbon