Editing Limestone (section)

== Limestone landscape ==
{{Main|Karst topography}}
[[File:Maczuga Herkulesa (background Castle Pieskowa Skała).jpg|thumb|left|[[Maczuga Herkulesa|The Cudgel of Hercules]], a tall limestone rock in Poland ([[Pieskowa Skała|Pieskowa Skała Castle]] in the background)]]
[[File:Cenote in valladolid mexico (21362599476).jpg|thumb|The [[Samulá]] [[cenote]] in [[Valladolid Municipality, Yucatán|Valladolid]], [[Yucatán]], [[Mexico]]]][[File:La Zaplaz, Piatra Craiului.jpg|thumb|La Zaplaz formations in the [[Piatra Craiului Mountains]], [[Romania]].]]Limestone is partially soluble, especially in acid, and therefore forms many erosional landforms. These include [[limestone pavement]]s, [[pot hole]]s, [[cenote]]s, caves and gorges. Such erosion landscapes are known as [[karsts]]. Limestone is less [[resistance (geology)|resistant]] to erosion than most [[igneous]] rocks, but more resistant than most other [[sedimentary rock]]s. It is therefore usually associated with hills and [[downland]], and occurs in regions with other sedimentary rocks, typically clays.<ref name="thornbury-1969">{{cite book |last1=Thornbury |first1=William D. |title=Principles of geomorphology |date=1969 |publisher=Wiley |location=New York |isbn=0-471-86197-9 |pages=303–344 |edition=2d}}</ref><ref>{{cite web |title=Karst Landscapes of Illinois: Dissolving Bedrock and Collapsing Soil |url=https://isgs.illinois.edu/outreach/geology-resources/karst-landscapes-illinois-dissolving-bedrock-and-collapsing-soil |website=Prairie Research Institute |publisher=Illinois State Geological Survey |access-date=26 December 2020 |archive-date=2 December 2020 |archive-url=https://web.archive.org/web/20201202003934/https://isgs.illinois.edu/outreach/geology-resources/karst-landscapes-illinois-dissolving-bedrock-and-collapsing-soil |url-status=dead }}</ref>

Karst regions overlying limestone bedrock tend to have fewer visible above-ground sources (ponds and streams), as surface water easily drains downward through [[Joint (geology)|joints]] in the limestone. While draining, water and organic acid from the soil slowly (over thousands or millions of years) enlarges these cracks, dissolving the calcium carbonate and carrying it away in [[Solution (chemistry)|solution]]. Most [[cave]] systems are through limestone bedrock. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation.<ref name="thornbury-1969" />

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]].<ref>{{cite journal|last1=Taylor|first1=P. D.|last2=Wilson|first2=M. A.|date=2003|title=Palaeoecology and evolution of marine hard substrate communities|journal=Earth-Science Reviews|volume=62|issue=1–2|pages=1–103|bibcode=2003ESRv...62....1T|doi=10.1016/S0012-8252(02)00131-9|url=http://www.wooster.edu/geology/Taylor%26Wilson2003.pdf|archive-url=https://web.archive.org/web/20090325233234/http://www.wooster.edu/geology/Taylor%26Wilson2003.pdf|url-status=dead|archive-date=2009-03-25}}</ref>

Bands of limestone emerge from the Earth's surface in often spectacular rocky outcrops and islands. Examples include the [[Rock of Gibraltar]],<ref name="Quaternary Science Reviews 23 (2004) 2017–2029">{{cite journal |last1=Rodrı́guez-Vidal |first1=J. |last2=Cáceres |first2=L.M. |last3=Finlayson |first3=J.C. |last4=Gracia |first4=F.J. |last5=Martı́nez-Aguirre |first5=A. |title=Neotectonics and shoreline history of the Rock of Gibraltar, southern Iberia |journal=Quaternary Science Reviews |date=October 2004 |volume=23 |issue=18–19 |pages=2017–2029 |doi=10.1016/j.quascirev.2004.02.008 |url=https://www.researchgate.net/publication/257823064|publisher=Elsevier (2004)|bibcode=2004QSRv...23.2017R |hdl=11441/137125 |access-date=23 June 2016|hdl-access=free }}</ref> the [[The Burren|Burren]] in County Clare, Ireland;<ref>{{cite web |last1=McNamara |first1=M. |last2= Hennessy |first2=R. |year=2010 |title=The geology of the Burren region, Co. Clare, Ireland |website=Project NEEDN, The Burren Connect Project |location=Ennistymon |publisher=Clare County Council |url=https://www.burrengeopark.ie/wp-content/uploads/2014/08/NEED-THE_GEOLOGY_OF_THE_BURREN_REGIONBurren-Techni.pdf |access-date=3 February 2021}}</ref> [[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| access-date=8 October 2006| url-status=dead| archive-url=https://web.archive.org/web/20061102184845/http://www.iwight.com/council/documents/policies_and_plans/udp/2002_pdfs/minerals.pdf| archive-date=2 November 2006}}</ref> England; the [[Great Orme]] in Wales;<ref>{{cite journal |last1=Juerges |first1=A. |last2=Hollis |first2=C. E. |last3=Marshall |first3=J. |last4=Crowley |first4=S. |title=The control of basin evolution on patterns of sedimentation and diagenesis: an example from the Mississippian Great Orme, North Wales |journal=Journal of the Geological Society |date=May 2016 |volume=173 |issue=3 |pages=438–456 |doi=10.1144/jgs2014-149|bibcode=2016JGSoc.173..438J |doi-access=free }}</ref> on [[Fårö]] near the Swedish island of [[Gotland]],<ref>{{cite journal |last1=Cruslock |first1=Eva M. |last2=Naylor |first2=Larissa A. |last3=Foote |first3=Yolanda L. |last4=Swantesson |first4=Jan O.H. |title=Geomorphologic equifinality: A comparison between shore platforms in Höga Kusten and Fårö, Sweden and the Vale of Glamorgan, South Wales, UK |journal=Geomorphology |date=January 2010 |volume=114 |issue=1–2 |pages=78–88 |doi=10.1016/j.geomorph.2009.02.019|bibcode=2010Geomo.114...78C }}</ref> the [[Niagara Escarpment]] in Canada/United States;<ref>{{cite journal |last1=Luczaj |first1=John A. |title=Geology of the Niagara Escarpment in Wisconsin |journal=Geoscience Wisconsin |date=2013 |volume=22 |issue=1 |pages=1–34 |url=https://www.researchgate.net/publication/325576131 |access-date=5 February 2021}}</ref> [[Notch Peak]] in Utah;<ref>{{cite journal |jstor=1302317|title=Conodont Fauna of the Notch Peak Limestone (Cambro-Ordovician), House Range, Utah|last1=Miller|first1=James F.|journal=Journal of Paleontology|year=1969|volume=43|issue=2|pages=413–439}}</ref> the [[Ha Long Bay]] National Park in Vietnam;<ref name=Thanh>{{cite journal|journal=Advances in Natural Sciences|volume=2|issue=3|issn=0866-708X|url=https://www.researchgate.net/publication/258604343|title=The outstanding value of the geology of Ha Long Bay|last1=Tran Duc Thanh|last2=Waltham Tony|date=1 September 2001}}</ref> and the hills around the [[Lijiang River]] and [[Guilin]] city in China.<ref name="Tony">{{cite book|last1=Waltham|first1=Tony|editor1-last=Migon|editor1-first=Piotr|title=Guangxi Karst: The Fenglin and Fengcong Karst of Guilin and Yangshuo, in Geomorphological Landscapes of the World|date=2010|publisher=Springer|isbn=978-90-481-3054-2|pages=293–302}}</ref>

The [[Florida Keys]], islands off the south coast of [[Florida]], are composed mainly of [[oolite|oolitic]] limestone (the Lower Keys) and the carbonate skeletons of [[coral]] reefs (the Upper Keys), which thrived in the area during interglacial periods when sea level was higher than at present.<ref>{{Cite journal|last=Mitchell-Tapping|first=Hugh J.|date=Spring 1980|title=Depositional History of the Oolite of the Miami Limestone Formation|journal=Florida Scientist|volume=43|issue=2|pages=116–125|jstor=24319647}}</ref>

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 [[Öland]], Sweden.<ref>Thorsten Jansson, ''Stora Alvaret'', Lenanders Tryckeri, [[Kalmar]], 1999</ref> Another area with large quantities of limestone is the island of Gotland, Sweden.<ref name=Laufeld1974>{{cite book |last=Laufeld |first=S. |year=1974 |title=Silurian Chitinozoa from Gotland |publisher=Universitetsforlaget |series=Fossils and Strata |issue=5 }}</ref> Huge quarries in northwestern Europe, such as those of Mount Saint Peter (Belgium/Netherlands), extend for more than a hundred kilometers.<ref>{{cite journal |last1=Pereira |first1=Dolores |last2=Tourneur |first2=Francis |last3=Bernáldez |first3=Lorenzo |last4=Blázquez |first4=Ana García |title=Petit Granit: A Belgian limestone used in heritage, construction and sculpture |journal=Episodes |date=2014 |volume=38 |issue=2 |page=30 |bibcode=2014EGUGA..16...30P |url=http://media.globalheritagestone.com/2016/12/Petit-Granit-Episodes.pdf |access-date=5 February 2021}}</ref>