Sedimentary Rocks

Science, Grade 6


Table Of Contents: Sedimentary Rocks

1. Formation of Sedimentary Rocks
Sedimentary rocks form in layers, or strata, that have been deposited and cemented together over millions of years.
2. Sedimentary Rock Categories
There are three categories of sedimentary rock—clastic, organic and chemical.
3. Clastic Sedimentary Rock
Clastic sedimentary rocks are made from pieces of pre-existing rocks that are transported by wind and water and deposited in a new location. Layers of sediment accumulate and become cemented together to form solid rock.
4. Clastic Sedimentary Rock Examples
Sandstone, shale and conglomerate are examples of clastic sedimentary rocks.
5. Organic Sedimentary Rock
Organic sedimentary rocks form when shell remains fossilize and become a layer of limestone on the ocean floor. A coral reef is an example of organic limestone formed from the buildup of coral skeletons.
6. Chemical Sedimentary Rock
Chemical sedimentary rocks form through precipitation or crystallization of dissolved minerals. Dissolved calcite forms fine-grained limestone that shows no fossilized remains.
7. Sedimentary Rock Uses
Limestone is primarily used for concrete and road construction. Coal is a type of organic sedimentary rock that is used as a solid fuel to produce electricity and heat.