Objectives Describe how sedimentary rocks form. List and describe the three major types of sedimentary rocks.
Vocabulary Words Sediment Erosion Deposition Compaction Cementation Clastic rock Organic rock Chemical rock
From Sediment to Rock Sedimentary rocks are formed from particles deposited by water and wind. –Sediments are small pieces of material that come from rocks or living things. –Water, wind, and ice can carry sediment and deposit in layers.
Ways Sediments are Turned to Rocks Erosion Deposition Compaction Cementation
Erosion Erosion occurs when running water or wind loosen and carry away rock fragments. –Rock fragments produced by forces breaking up and wearing away rocks on the Earth’s surface.
Deposition This is the process by which sediment settles out of the water or wind carrying it. –Sediments include rock particles, shells, bones, leaves, stems, and remains from other living things.
Compaction The process that presses sediments together. –Each layer presses down the the previous layer. –The weight of the layers further compacts the sediments, squeezing them tightly together. –Each layer remains visible. This process takes place over millions of years.
Cementation The process in which dissolved minerals crystallize and glue particles of sediment together. This process takes place over millions of years.
Types of Sedimentary Rock Clastic Rocks Organic Rocks Chemical Rocks
Clastic Rock It is a sedimentary rock that forms when rock fragments are squeezed together. They are grouped by size of the rock fragments by which they’re made. Examples include: Shale, sandstone, conglomerate, and breccia. conglomerate
Organic Rock Forms where the remains of plants and animals are deposited in thick layers. Examples include: Coal and limestone Coal
Chemical Rocks Forms when minerals that are dissolved in a solution crystallize. Can also form when mineral deposits left when seas or lakes evaporate. Examples include: gypsum and limestone. Gypsum