Dolostone or dolomite rock is a sedimentary carbonate rock that contains a high percentage of the mineral dolomite. In old U.S.G.S. publications it was referred to as magnesian limestone. Most dolostone formed as a magnesium replacement of limestone or lime mud prior to lithification. It is resistant to erosion and can either contain bedded layers or be unbedded. It is less soluble than limestone in weakly acidic groundwater, but it can still develop solution features over time.
Recent research has found dolomite formation under anaerobic conditions in supersaturated saline lagoons along the Rio de Janeiro coast of Brazil, namely, Lagoa Vermelha and Brejo do Espinho. It is often thought, that dolomite will develop only with the help of sulfate-reducing bacteria (e.g. Desulfovibrio brasiliensis).
Even so, the actual role of bacteria in the low-temperature formation of dolomite remains to be demonstrated in reproducible laboratory experiments. The specific mechanism of dolomite formation, involving for example sulfate-reducing bacteria, has not yet been documented.
The term dolostone was introduced to avoid confusion with the mineral dolomite. The usage of the term dolostone is controversial because the name dolomite was first applied to the rock during the late 18th century and thus has technical precedence. The use of the term dolostone is not recommended by the Glossary of Geology published by the American Geological Institute. It is, however, used in some geological publications.
- Blatt, Harvey; Tracy, Robert J. (1996). Petrology; Igneous, Sedimentary, and Metamorphic (2nd ed.). W. H. Freeman. pp. 317–323. ISBN 0-7167-2438-3.
- Tucker, M. E.; V. P., Wright (1990). Carbonate Sedimentology. Blackwell Scientific Publications. ISBN 0-632-01472-5.
- Zenger, D. H.; Mazzullo, S. J. (1982). Dolomitization. Hutchinson Ross. ISBN 0-87933-416-9.
- Zenger & Mazzullo, 1982
|Wikimedia Commons has media related to Dolomite rock.|
|This article related to petrology is a stub. You can help Wikipedia by expanding it.|