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

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

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

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

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

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

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

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

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

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

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