Limestone: Difference between revisions
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Mr. po had applesause this morning |
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{{intro-tooshort}} |
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{{otheruses}} |
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[[Image:Limestone cropping.jpg|thumb|right|Limestone cropping at [[São Pedro de Moel]] beach, [[Marinha Grande]], Portugal.]] |
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[[Image:IronImpregnationsLimestone2.jpg|thumb|right|Iron impregnations in limestone]] |
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[[Image:OrdOutcropTN.JPG|thumb|right|A stratigraphic section of [[Ordovician]] limestone exposed in central [[Tennessee]], U.S. The less-resistant and thinner beds are composed of [[shale]]]] |
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[[Image:CarmelOoids.jpg|thumb|right|Thin-section view of a Middle [[Jurassic]] limestone in southern Utah. The round grains are [[ooid]]s; the largest is 1.2 mm in diameter. This limestone is an oosparite.]] |
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'''Limestone''' is a [[sedimentary rock]] composed largely of the [[mineral]] [[calcite]] ([[calcium carbonate]]: CaCO<sub>3</sub>). |
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== Description== |
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Limestone often contains variable amounts of [[silica]] in the form of [[chert]] and/or [[flint]], as well as varying amounts of [[clay]], [[silt]] and [[sand]] as disseminations, nodules, or layers within the rock. The primary source of the calcite in limestone is most commonly [[marine biology|marine organisms]]. These organisms secrete shells that settle out of the water column and are deposited on [[ocean]] floors as [[Pelagic zone|pelagic]] ooze or alternatively are conglomerated in a coral reef (see [[lysocline]] for information on calcite dissolution). Secondary calcite may also be deposited by [[Supersaturation|supersaturated]] [[Meteorology|meteoric]] waters ([[groundwater]] that [[Precipitation (chemistry)|precipitates]] the material in [[cave]]s). This produces [[speleothem]]s such as [[stalagmite]]s and [[stalactite]]s. Another form taken by calcite is that of [[oolite]]s (oolitic limestone) which can be recognized by its granular appearance. |
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Limestone makes up about 10% of the total volume of all sedimentary rocks.<ref> {{cite web |url=http://www.mine-engineer.com/mining/mineral/calcite.htm | title=Calcite | accessdate=2008-02-13}}</ref><ref> {{cite web |url=http://encarta.msn.com/encyclopedia_761565838/Limestone_(mineral).html | title=Limestone (mineral) |accessdate=2008-02-13}}</ref> Limestones may also form in both [[lacustrine]] and [[evaporite]] [[Sedimentary depositional environment|depositional environments]]<ref>[http://jgs.lyellcollection.org:/cgi/content/abstract/156/3/535]|Trewin,N.H. & Davidson,R.G. 1999. Lake-level changes, sedimentation and faunas in a Middle Devonian basin-margin fish bed, Journal Geological Society, 156, 535-548</ref><ref>[http://www.glossary.oilfield.slb.com/Display.cfm?Term=evaporite Oilfield Glossary: Term 'evaporite'<!-- Bot generated title -->]</ref>. |
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Calcite can be either [[solvation|dissolved]] by groundwater or [[precipitate]]d by groundwater, depending on several factors including the water temperature, [[acidity|pH]], and dissolved [[ion]] concentrations. Calcite exhibits an unusual characteristic called [[retrograde solubility]] in which it becomes less soluble in water as the temperature increases. |
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When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures. |
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[[Karst]] [[topography]] and [[cave]]s develop in carbonate rocks due to their [[solubility]] in dilute [[acid]]ic [[groundwater]]. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation. |
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Coastal limestones are often eroded by organisms which bore into the rock by various means. This process is known as [[bioerosion]]. It is most common in the tropics, and it is known throughout the [[fossil record]] (see Taylor and Wilson, 2003). |
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Because of impurities, such as [[clay]], sand, organic remains, [[iron oxide]] and other materials, many limestones exhibit different colors, especially on [[Weathering|weathered]] surfaces. Limestone may be crystalline, clastic, granular, or massive, depending on the method of formation. Crystals of calcite, [[quartz]], [[dolomite]] or [[barite]] may line small cavities in the rock. [[Folk classification|Folk]] and [[Dunham classification|Dunham]] classifications are used to describe limestones more precisely. |
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[[Travertine]] is a banded, compact variety of limestone formed along streams, particularly where there are waterfalls and around [[Hot spring|hot]] or cold springs. Calcium carbonate is deposited where evaporation of the water leaves a solution that is supersaturated with chemical constituents of calcite. [[Tufa]], a porous or cellular variety of travertine, is found near waterfalls. [[Coquina]] is a poorly consolidated limestone composed of pieces of [[coral]] or [[Animal shell|shell]]s. |
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During regional [[metamorphism]] that occurs during the mountain building process ([[orogeny]]) limestone recrystallizes into [[marble]]. |
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Limestone is a [[parent material]] of [[Mollisol]] [[soil]] group. |
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== Limestone landscape == |
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{{main|Karst topography}} |
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Limestone is partially soluble, especially in [[acid]], and therefore forms many [[erosion]]al [[landform]]s. These include [[limestone pavement]]s, [[pot hole]]s, [[cenote]]s, [[cave]]s and [[gorge]]s. Such erosion landscapes are known as karsts. Limestone is less [[resistance (geology)|resistant]] than most [[igneous]] rocks, but more resistant than most other [[sedimentary rocks]]. Limestone is therefore usually associated with hills and [[downland]] and occurs in regions with other sedimentary rocks, typically [[clay]]s. |
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Bands of limestone emerge from the [[Earth]]'s surface in often spectacular rocky outcrops and [[island]]s. Examples include the [[The Burren|Burren]] in Co. Clare, Ireland; the [[Verdon Gorge]] in [[France]]; [[Malham Cove]] in [[North Yorkshire]] and the [[Isle of Wight]]<ref>{{cite web | url=http://www.iwight.com/council/documents/policies_and_plans/udp/2002_pdfs/minerals.pdf| title=Isle of Wight, Minerals | accessdate=2006-10-08}}</ref>, [[England]]; on [[Fårö]] near the Swedish island of [[Gotland]], the [[Niagara Escarpment]] in [[Canada]]/[[United States]], Notch Peak in [[Utah]], and the [[Ha Long Bay]] National Park in [[Vietnam]]. |
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Unique habitats are found on [[alvar]]s, extremely level expanses of limestone with thin soil mantles. The largest such expanse in [[Europe]] is the [[Stora Alvaret]] on the island of [[Oland]], [[Sweden]]. Another area with large quantities of limestone is the island of [[Gotland]], Sweden. Huge quarries in northwestern Europe, such as those of Mount Saint Peter (Belgium/Netherlands), extend for more than a hundred kilometers. |
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The world's largest limestone quarry is at [[Michigan Limestone and Chemical Company]] in [[Rogers City, Michigan]].<ref>[http://www.michmarkers.com/startup.asp?startpage=S0214.htm Michigan Markers]</ref> |
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== Uses of limestone == |
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Limestone is very common in [[architecture]], especially in [[North America]] and [[Europe]]. Many landmarks across the world, including the pyramids in [[Egypt]], are made of limestone. So many buildings in [[Kingston, Ontario|Kingston, Ontario, Canada]] were constructed from it that it is nicknamed the 'Limestone City'. <ref> {{cite web |url= http://www.citylifeontario.com/kingston/ | title=Welcome to the Limestone City |accessdate=2008-02-13}} </ref> On the island of [[Malta]], a variety of limestone called Globigerina limestone was for a long time the only building material available, and is still very frequently used on all types of buildings and sculptures. Limestone is readily available and relatively easy to cut into blocks or more elaborate carving. It is also long-lasting and stands up well to exposure. However, it is a very heavy material, making it impractical for tall buildings, and relatively expensive as a building material. |
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[[Image:Riley (Kansas) County Courthouse 1.jpg|thumb|right|Courthouse built of limestone in [[Manhattan, Kansas]]]] |
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[[Image:Litography press with map of Moosburg 01.jpg|thumb|right|A limestone plate with a negative map of [[Moosburg]] in [[Bavaria]] is prepared for a [[lithography]] print]] |
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Limestone was most popular in the late 19th and early 20th centuries. [[Train station]]s, [[bank]]s and other structures from that era are normally made of limestone. Limestone is used as a facade on some [[skyscraper]]s, but only in thin plates for covering rather than solid blocks. In the United States, [[Indiana]], most notably the Bloomington area, has long been a source of high quality quarried limestone, called [[Indiana limestone]]. Many famous buildings in [[London]] are built from [[Portland limestone]]. |
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Limestone was also a very popular building block in the Middle Ages in the areas where it occurred since it is hard, is durable, and commonly occurs in easily accessible surface exposures. Many medieval churches and castles in Europe are made of limestone. [[Beer stone]] was a popular kind of limestone for medieval buildings in southern England. |
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Limestone and marble are very reactive to acid solutions, making [[acid rain]] a significant problem. Many limestone statues and building surfaces have suffered severe damage due to acid rain. Acid-based cleaning chemicals can also etch limestone, which should only be cleaned with a neutral or mild alkaline-based cleaner. |
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Other uses include: |
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* The manufacture of [[quicklime]] (calcium oxide) and [[slaked lime]] (calcium hydroxide); |
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* [[Cement]] and [[mortar (masonry)|mortar]]; |
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* Pulverized limestone is used as a soil conditioner to neutralize acidic soil conditions; |
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* Crushed for use as [[construction aggregate|aggregate]]—the solid base for many roads; |
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* [[Geological formation]]s of limestone are among the best [[petroleum]] reservoirs; |
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* As a [[reagent]] in [[flue gas desulfurization|desulfurizations]]; |
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* Glass making, in some circumstances; |
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* Added to paper, plastics, paint, tiles, and other materials as both white pigment and a cheap filler. |
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* Toothpaste |
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* Suppression of methane explosions in underground coal mines |
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* Added to bread and cereals as a source of calcium |
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== Notes == |
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<!-- this 'empty' section displays references defined elsewhere --> |
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{{reflist}} |
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== References == |
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* Taylor, P.D. and Wilson, M.A., 2003. Palaeoecology and evolution of marine hard substrate communities. Earth-Science Reviews 62: 1-103.[http://www.wooster.edu/geology/Taylor%26Wilson2003.pdf] |
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== See also == |
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{{Commons cat|Limestones}} |
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* [[List of types of limestone]] |
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* [[Chalk]] |
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* [[Coral sand]] |
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* [[Calcium carbonate]] |
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* [[In Praise of Limestone]] |
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[[Category:Sedimentary rocks]] |
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[[Category:Limestone| ]] |
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[[ar:حجر جيري]] |
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[[an:Calsinera]] |
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[[zh-min-nan:Chio̍h-hoe-giâm]] |
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[[bs:Krečnjak]] |
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[[bg:Варовик]] |
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[[ca:Pedra calcària]] |
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[[cs:Vápenec]] |
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[[cy:Calchfaen]] |
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[[de:Kalkstein]] |
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[[et:Lubjakivi]] |
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[[el:Ασβεστόλιθος]] |
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[[es:Caliza]] |
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[[eo:Kalkoŝtono]] |
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[[eu:Kareharri]] |
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[[fr:Calcaire]] |
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[[gl:Caliza]] |
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[[ko:석회암]] |
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[[hr:Vapnenac]] |
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[[id:Batu kapur]] |
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[[is:Kalksteinn]] |
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[[it:Calcare]] |
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[[he:אבן גיר]] |
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[[lv:Kaļķakmens]] |
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[[lt:Klintis]] |
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[[hu:Mészkő (kőzet)]] |
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[[mt:Ġebla tal-ġir]] |
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[[nl:Kalksteen]] |
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[[ja:石灰岩]] |
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[[no:Kalkstein]] |
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[[nn:Kalkstein]] |
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[[pl:Wapień]] |
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[[pt:Calcário]] |
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[[qu:Isku]] |
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[[ru:Известняк]] |
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[[simple:Limestone]] |
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[[sk:Vápenec]] |
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[[sl:Apnenec]] |
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[[sr:Кречњак]] |
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[[fi:Kalkkikivi]] |
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[[sv:Kalksten]] |
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[[th:หินปูน]] |
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[[tl:Batong-apog]] |
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[[vi:Đá vôi]] |
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[[tr:Kireç taşı]] |
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[[uk:Вапняк]] |
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[[zh:石灰岩]] |
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Revision as of 22:02, 9 December 2008
Mr. po had applesause this morning