Of the three classes of rock, sedimentary rock<\/i> is the least plentiful, although the majority of surface rocks are sedimentary.\u00a0 Sedimentary rock is formed near the Earth\u2019s surface by the accumulation and cementation of fragments of earlier rocks, minerals and organisms. They are the product of the erosion of existing rocks. \u00a0Eroded material accumulates and then erosion and weathering transport materials that are deposited as sediment.\u00a0 Pieces of rock or organic particles settle and accumulate either in the sea or on land.\u00a0 This particulate matter undergoes compaction and cementation in a process known as diagenesis<\/i>.\u00a0 Sedimentary rocks are deposited in horizontal layers and are sometimes referred to as stratified<\/i> rocks.\u00a0 Often sedimentary rocks contain fossils.<\/p>\n
There are three major categories of sedimentary rocks:\u00a0 Detrital, Chemical, and Biological.<\/p>\n
Detrital rocks<\/i> or clastic rocks <\/i>consist of fragments of pre-existing rocks that have been weathered away, transported and deposited by clast<\/i> or particle size.\u00a0 Detrital sedimentary rocks are those for which the material has been transported as solid materials.\u00a0 Mineral grains or rock fragments formed by weathering are called clastic or detrital material.\u00a0 The fragments of pre-existing rocks or minerals that make up a sedimentary rock are called clasts.\u00a0 Clasts indicate that particles have been broken and transported. Clastic sedimentary rocks are primarily classified on the size of their clasts from boulder and very coarse gravel down to fine sand, mud and clay.<\/p>\n
Chemical rocks<\/i> form as water evaporates from a lake or ocean.\u00a0 Minerals form due to precipitation and grow attached to previously formed crystals.\u00a0 Rock is composed of intergrown mineral crystals.\u00a0 These sedimentary rocks occur when minerals or mineraloids (without fixed composition) are precipitated directly from water, or are concentrated by organic matter. Components have not been transported prior to deposition and therefore no clasts are present.\u00a0 An example of a non-clastic texture would be crystalline material.<\/p>\n
Biological rocks<\/i> are formed by the compaction of organic materials.\u00a0 Coal has high carbon content and amber is formed from an ancient, hardened tree sap.<\/p>\n
The twelve most common sedimentary rocks are listed below and are organized by the three major categories.<\/p>\n
Clastic (Fragmental) Sedimentary Rocks<\/b><\/p>\n Chemical Sedimentary Rocks<\/b><\/p>\n Biological Sedimentary Rocks<\/b><\/p>\n Sedimentary Rock Building Materials.\u00a0 <\/b>For the purpose of masonry, only half of the sedimentary rocks in the above list are commonly used as building materials.<\/p>\n Conglomerates<\/b> and breccia<\/b> are clastic rocks with large particle sizes.\u00a0 The texture gives them decorative interest.\u00a0 Sandstone<\/b> is a clastic rock with medium sand particles sizes.\u00a0 Sandstone is quarried all over the world and comes in a tremendous variety of strength and color.\u00a0 It includes Flagstone<\/b> and also a variation known as Greywacke<\/b>.\u00a0 Limestone<\/b> can be clastic or chemical and also comes in a huge variety.\u00a0 Travertine<\/b> is a variety of limestone.\u00a0 Dolomite<\/b> is very similar to limestone with a slight chemical difference.<\/p>\n Photos:<\/strong><\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n <\/p>\n","protected":false},"excerpt":{"rendered":" Of the three classes of rock, sedimentary rock is the least plentiful, although the majority of surface rocks are sedimentary.\u00a0 Sedimentary rock is formed near the Earth\u2019s surface by the accumulation and cementation of fragments of earlier rocks, minerals and organisms. They are the product of the erosion of existing rocks. \u00a0Eroded material accumulates and … <\/p>\n\n
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