Limestone

Article By:

Moore, Clyde H., Jr. Department of Geology and Geological Engineering, Colorado School of Mines, Golden, Colorado.

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.383000

A common sedimentary rock composed predominantly of carbonates of calcium and magnesium. Limestones are the most voluminous of the nonsiliciclastic sedimentary rocks (Fig. 1). In the strict sense, limestones refer to sedimentary rocks composed of the calcium carbonate mineral calcite (CaCO₃). Those rocks, dominated by the magnesium–calcium carbonate mineral dolomite [CaMg(CO₃)₂], are known as dolomites or dolostones. Although most limestones are similar in chemical and mineralogical composition, the complex organic and chemical origins of carbonate sediments lead to a wide range of textures and fabrics in the resulting limestones. These textures and fabrics share significant parallels with those found in siliciclastic rocks, and they are quite useful for the classification and determination of depositional environments for limestones. Limestones and dolomites are used commercially as building materials and as a source for industrial and agricultural lime. In addition, limestones and dolomites are important reservoirs for oil and gas and are the hosts for important mineral deposits, including lead, zinc, silver, and fluorite. See also: Lime (industry); Ore and mineral deposits; Petroleum geology; Stone and stone products

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