Made from an accumulation of various types of sediments Sedimentary Rocks Made from an accumulation of various types of sediments

What is sediment? Fragments that result from the breaking (weathering) of rocks, minerals, and organic matter. Ex. Gravel, clay, silt, pebbles, sand, mud, shells, dirt

MOST SEDIMENTARY ROCK FORMS UNDER WATER! Ex. Limestone, halite Limestone is a rock that is composed primarily of calcium carbonate. It can form organically from the accumulation of shell, coral, algal and fecal debris. It can also form chemically from the precipitation of calcium carbonate from lake or ocean water. Limestone is used in many ways. Some of the most common are: production of cement, crushed stone and acid neutralization Rock Salt is a chemical sedimentary rock that forms from the evaporation of ocean or saline lake waters. It is also known by the mineral name "halite". It is rarely found at Earth's surface, except in areas of very arid climate. It is often mined for use in the chemical industry or for use as a winter highway treatment. Some halite is processed for use as a seasoning for food.

Sedimentary rock forms from these processes: Weathering, Erosion, and Deposition Compaction: sediments are pushed together and as a result, water and air are squeezed out. Cementation: water passes through the sediments and dissolved minerals left behind act as a cement to hold the sediments together. Precipitation: minerals clump together and fall out of solution Evaporation: Water evaporates and leaves dissolved minerals behind.

Three Types of Sedimentary Rocks

Clastic Formed from fragments of other rocks which have been weathered and eroded Classified by the size of the sediments (coarse-pebbles or larger, medium-sand sized, or fine-clay or silt sized) Ex. Sandstone (sand), shale (silt or clay), conglomerate (round pebbles), and breccia (angular pieces)

How are breccia and conglomerate different? Breccia is a clastic sedimentary rock that is composed of large (over two millimeter diameter) angular fragments Conglomerate is a clastic sedimentary rock that contains large (greater then two millimeters in diameter) rounded particles.

Shale is a clastic sedimentary rock that is made up of clay-size (less then 1/256 millimeter in diameter) weathering debris. It typically breaks into thin flat pieces Sandstone is a clastic sedimentary rock made up mainly of sand-size (1/16 to 2 millimeter diameter) weathering debris. Environments where large amounts of sand can accumulate include beaches, deserts, flood plains and deltas.

Chemical Formed from minerals that were once dissolved in water. Either the minerals “settle” out of the water (precipitates) or the water evaporates leaving the minerals behind (evaporites) Classified by their mineral composition Ex. Chemical Limestone (CaCO3), gypsum (CaSO4), halite (NaCl)

Organic Formed from the remains or traces of animals and/or plants Ex. Coal (plants), chalk (animal skeletons), organic limestone (shells-CaCO3) Coccolithophores are the most important group of chalk forming plankton. Each miniscule individual has a spherical skeleton called a cocosphere, formed from a number of calcareous discs called coccoliths. After death, most coccospheres and coccoliths collapse into their constituent parts. Most chalks formed during the Cretaceous period, between 100 and 60 million years ago, and chalks of this age can be found around the world.

Features of Sedimentary Rocks Stratification: (aka. Layering) occurs when there is a change in the kind of sediment deposited. Ex. Grand Canyon

Features of Sedimentary Rocks Ripple marks: formed from the action of wind or water on sand (seen in sandstone)

Features of Sedimentary Rocks Fossils: remains or traces of plants and/or animals http://www.google.com/imgres?imgurl=http://www.treasure-hunting-team.com/Pictures/Fossil-Fish-2.jpg&imgrefurl=http://www.treasure-hunting-team.com/a27-treasure-hunting-for-fossil-fish.php&usg=__811kSGYVnjP_BCYdRMYnm_W1gOQ=&h=351&w=468&sz=39&hl=en&start=0&sig2=kGN8z_T0tf_SN3pX-sLBkA&zoom=1&tbnid=CIxmWv3evjEsOM:&tbnh=156&tbnw=208&ei=4SxMTaGaE8ycgQeX6IHoDw&prev=/images%3Fq%3Dfossil%26um%3D1%26hl%3Den%26sa%3DN%26biw%3D1280%26bih%3D685%26tbs%3Disch:1&um=1&itbs=1&iact=hc&vpx=785&vpy=124&dur=1303&hovh=194&hovw=259&tx=97&ty=86&oei=4SxMTaGaE8ycgQeX6IHoDw&esq=1&page=1&ndsp=16&ved=1t:429,r:3,s:0 http://www.fossilmuseum.net/Fossil_Sites/mcabee/Camaecyparis/Camaecyparis.htm