1. Chapter 3 Lesson 2 Sedimentary Rocks
Earth Science Unit 1
Chapter 3
Lesson 2
Sedimentary Rocks

2. Sediments
Defined: Particles of minerals, rock fragments, shells, leaves, bones, and fragments of other once living things

3. Sedimentary Rocks
Defined: rocks that form from sediments that are compressed and cemented together
The process of creating sedimentary rocks is known as Lithification

4. How are they Formed?
Step 1: Compaction- pressure pushes sediments together, leaving little space between them
Step 2: Cementation- water carries dissolved minerals through the sediments and leaves them in the open spaces

5. How are they Classified?
They are classified by the way they form
Clastic Rocks- Made from separate rock particles and fragments that were eroded away from older rocks
Examples: Sandstone, Shale

6. Classification Continued…
Congiomerate rock- A rock composed of rounded, pebble-sized rock fragments
They form where sediments are deposited
Example: mouths of rivers and beaches
Breccla- a Type of congiomerate rock composed of sharp cornered fragment

7. Sandstone
Defined: A clastic rock composed of rounded sand sized grains
Contains quartz
Very porous, so water can move easily through it

8. Shale
Defined: A clastic rock composed of clay-sized particles in flat layers
Layers a brittle and easily broken
The most common sedimentary rock

9. Chemical Sedimentary Rocks
Composed of minerals that were once dissolved in water
Formed after water evaporates
Rock salt and gypsum are two examples

10. Organic Sedimentary Rocks
Rocks made from the organic material of decaying organisms
Coal is an example

11. Questions to Answer
What is an example of how chemical sedimentary rocks are formed?