Sedimentary Rocks What are Sedimentary Rocks n Sedimentary

Sedimentary Rocks

What are Sedimentary Rocks? n Sedimentary Rock: Type of rock that forms when particles from other rocks or the remains of plants and animals are pressed and cemented together. n Sediment: Small, solid pieces of material that come from rocks or living things. – May Include: § Particles of rock § Shells or bones § Leaves, stems, or roots

What are Sedimentary Rocks?

From Sediment to Rock n Most sedimentary rocks are formed through a series of processes. – 1) Erosion § Running water, wind, ice, or gravity moves weathered rock or soil § These forces break apart rock’s on the Earth’s surface

From Rock to Sediment – 2) Deposition § Process by which sediment settles out of the water or wind carrying it § May sink to the bottom of ocean, lake, or stream – 3) Compaction § Process that presses sediments together § Thick layers may build up over millions of years, pressing down on the layers below them § Layers often remain visible

From Rock to Sediment – 4) Cementation § While compacting is taking place, the minerals in the rock slowly dissolve in the water § Process in which dissolved minerals crystallize and glue particles of sediment together

Types of Sedimentary Rocks n Clastic Rocks – Sedimentary rock that forms when rock fragments are squeezed together – Common Clastic Rocks § Shale-forms from tiny particles of clay § Sandstone-forms from the sand on beaches, the ocean floor, riverbeds, and sand dunes § Conglomerate-rock fragments with rounded edges § Breccia-rock made up of large fragments with sharp edges

Clastic Rocks

Types of Sedimentary Rocks n Organic Rocks – Forms where the remains of plants and animals are deposited in thick layers – Two important organic sedimentary rocks: § Coal-forms from the remains of swamp plants buried in water § Limestone-forms in the ocean from calcite deposits of dead coral, clams, and oysters

Organic Rocks

Types of Sedimentary Rocks n Chemical Rocks – Forms when minerals dissolve in a solution and crystallize § Rock Salt-evaporation of halite § Limestone-evaporation of calcite