Editing Sedimentary rock (section)

==Classification based on composition==
[[File:Cretaceous Gastropod Fossils Lebanon.jpg|thumb|upright=1.2|[[Fossil]]s of [[Nerinea]] marine [[gastropods]] of [[Late Cretaceous]] ([[Cenomanian]]) age, in limestone in [[Lebanon]]]]

Alternatively, sedimentary rocks can be subdivided into compositional groups based on their mineralogy:
* '''[[Clastic rock|Siliciclastic sedimentary rocks]]''', are dominantly composed of [[silicate mineral]]s. The sediment that makes up these rocks was transported as [[bed load]], [[suspended load]], or by [[sediment gravity flows]]. Siliciclastic sedimentary rocks are subdivided into [[conglomerate (geology)|conglomerates]] and [[breccia]]s, [[sandstone]], and [[mudrock]]s.
* '''[[Carbonate rock|Carbonate sedimentary rocks]]''' are composed of [[calcite]] (rhombohedral {{chem|CaCO|3}}), aragonite (orthorhombic {{chem|CaCO|3}}), dolomite ({{chem|CaMg(CO|3|)|2}}), and other carbonate minerals based on the {{chem|CO|3|2-}} ion. Common examples include [[limestone]] and the rock [[Dolomite (rock)|dolomite]].
* '''[[Evaporite|Evaporite sedimentary rocks]]''' are composed of minerals formed from the evaporation of water. The most common evaporite minerals are [[carbonate minerals|carbonates]] (calcite and others based on {{chem|CO|3|2-}}), [[chloride]]s (halite and others built on {{chem|Cl|-}}), and [[sulfate mineral|sulfates]] ([[gypsum]] and others built on {{chem|SO|4|2-}}). Evaporite rocks commonly include abundant halite (rock salt), [[gypsum]], and [[anhydrite]].
* '''[[Organic-rich sedimentary rocks]]''' have significant amounts of organic material, generally in excess of 3% [[total organic carbon]]. Common examples include [[coal]], [[oil shale]] as well as [[source rock]]s for oil and natural gas.
* '''[[Siliceous rock|Siliceous sedimentary rocks]]''' are almost entirely composed of silica ({{chem|SiO|2}}), typically as [[chert]], [[opal]], [[chalcedony]] or other microcrystalline forms.
* '''[[Iron-rich sedimentary rocks]]''' are composed of >15% iron; the most common forms are [[banded iron formation]]s and [[ironstone]]s.{{sfn|Prothero|Schwab|2004}}
* '''[[Phosphorite|Phosphatic sedimentary rocks]]''' are composed of phosphate minerals and contain more than 6.5% [[phosphorus]]; examples include deposits of [[phosphate nodule]]s, bone beds, and phosphatic mudrocks.{{sfn|Boggs|2006}}