Types of Sedimentary Rocks SWBAT describe the types of clastic sedimentary rocks; explain how chemical sedimentary rocks form; describe organic sedimentary rocks; recognize the importance of sedimentary rocks

Clastic Sedimentary Rocks Clastic Organic Chemical Formed from abundant deposits of loose sediments found on Earth’s surface. Most common type of sedimentary rock. Classified by their grain size Formed from the remains of once-living things. Limestone is the most common, and is composed of calcite. During chemical weathering minerals are carried into lakes and when water evaporates the dissolved minerals are left behind. They can also precipitate from a super solution.

Grain Size What size particles do coarse-grained clastics have? –Gravel sized rocks and minerals What size particles do medium-grained clastics have? –Sand sized rocks and minerals What size particles do fine-grained clastics have? –Silt sized grains

Clastic Sediments Porosity –The percentage of open spaces between grains in a rock Critical thinking: Why might it be important to have both fine grained and medium grained layers in an oil field? –The larger grain has a higher porosity, allowing oil to flow freely, while the fine grained layers would trap the oil

Chemical Sedimentary Rocks Evaporites –The layer of chemical sedimentary rocks left after settling out of a solution, or from the solution evaporating What are the 3 most common evaportie minerals? –Calcite (CaSO 4 ) –Halite (NaCl) –Gypsum (CaSO 4 )

Organic Sedimentary Rocks What are organic sedimentary rocks composed of? –The remains of once living things; shells, plant materials What is the importance of sedimentary rocks? –Give geologists an idea of the surface conditions in Earth’s past; river flows, shorelines, animal and plant information