Rocks that are formed in flat layers called strata Sedimentary Rocks Rocks that are formed in flat layers called strata

Sedimentary Rocks Can Be Divided into Three Categories CLASTIC CHEMICAL ORGANIC

CLASTIC SEDIMENTARY ROCK When sediments are deposited, they settle to the bottom based on particle size. This is called stratification. These layers are called strata.

Classification of Clastic Rocks Clastic sedimentary rocks are not classified by mineral composition They are classified by the SIZE and SHAPE of the particles of sediment

Compaction and Cementation As layers build up, the particles get pressed together. Water is squeezed out and the particles are cemented together by minerals

Clastic Sedimentary Rocks Examples Shale Made of mud and silt particles Often breaks off in flat sheets

Clastic Sedimentary Rocks Examples Sandstone Made of sand particles cemented together Different colors based on type sand particles

Clastic Sedimentary Rocks Examples Conglomerate Made of pebbles or rounded stones Looks like natural concrete

Organic Sedimentary Rocks Formed from the remains of living things Shells of sea creatures Dinosaur/ancient creature remains Decayed plant material

Organic Sedimentary Rock Examples Bituminous Coal Made from the remains of decayed plant material Used as a fossil fuel mostly for making electricity

Fossiliferous Limestone Formed from the remains of sea creatures cemented together Contains the mineral calcite (calcium carbonate)

Organic Sedimentary Rock Examples Chalk Made from the remains of microscopic organisms First used on chalkboards

Chemical Sedimentary Rocks Formed from dissolved minerals in water When water evaporates, the minerals are left behind and crystallize Most common places to find this: Where ancient seas evaporated Caves

Chemical Sedimentary Rock Examples Limestone Contains calcite Can form stalactites and stalagmites in caves

Chemical Sedimentary Rock Examples Halite also known as rock salt Forms when ocean water evaporates