Editing Strait of Gibraltar (section)

==Geology==
[[File:StraitOfGibraltar.JPG|thumb|A view across the Strait of Gibraltar taken from the hills above [[Tarifa]], [[Spain]]]]
The seabed of the Strait is composed of [[synorogenic]] [[Betic-Rif]] [[clay]]ey [[flysch]] covered by [[Pliocene]] and/or [[Quaternary]] calcareous sediments, sourced from thriving cold water coral communities.<ref>De Mol, B., et al. 2012. "Ch. 45: Cold-Water Coral Distribution in an Erosional Environment: The Strait of Gibraltar Gateway", in: Harris, P. T.; Baker, E. K. (eds.), ''Seafloor geomorphology as benthic habitat: [[GEOHAB]] Atlas of seafloor geomorphic features and benthic habitats''. Elsevier, Amsterdam, pp. 636–643.</ref> Exposed bedrock surfaces, coarse sediments and local sand dunes attest to the strong bottom current conditions at the present time.{{citation needed|date=June 2023}}

Around 5.9&nbsp;million years ago, the connection between the Mediterranean Sea and the Atlantic Ocean along the [[Betic corridor|Betic]] and [[Rifan Corridor]] was progressively restricted until its total closure, effectively causing the salinity of the Mediterranean to rise periodically within the [[gypsum]] and salt deposition range, during what is known as the [[Messinian salinity crisis]]. In this [[chemistry|water chemistry]] environment, dissolved [[minerals|mineral concentrations]], temperature and stilled water currents combined and occurred regularly to [[precipitate]] many mineral salts in layers on the seabed. The resultant accumulation of various huge salt and mineral deposits about the Mediterranean basin are directly linked to this era. It is believed that this process took a short time, by geological standards, lasting between 500,000 and 600,000 years.{{citation needed|date=June 2023}}

It is estimated that, were the Strait closed even at today's higher sea level, most water in the [[Mediterranean basin]] would evaporate within a thousand years, as it is believed to have done then, and such an event would lay down mineral deposits like the salt deposits now found under the sea floor all over the Mediterranean.{{citation needed|date=June 2023}}

After a lengthy period of restricted intermittent or no water exchange between the Atlantic Ocean and Mediterranean basin, approximately 5.33&nbsp;million years ago,<ref>At the [[Miocene]]/[[Pliocene]] boundary, c. 5.33 million years before the present</ref> the Atlantic–Mediterranean connection was completely reestablished through the Strait of Gibraltar by the [[Zanclean flood]], and has remained open ever since.<ref>[[Preston Cloud|Cloud, P.]], ''Oasis in space. Earth history from the beginning'', New York: W.W. Norton & Co. Inc., p. 440. {{ISBN|0-393-01952-7}}</ref> The erosion produced by the incoming waters seems to be the main cause for the present depth of the Strait ({{cvt|900|m|ft fathom}} at the narrows, {{cvt|280|m|ft fathom}} at the [[Camarinal Sill]]). The Strait is expected to close again as the [[African Plate]] moves northward relative to the [[Eurasian Plate]],<ref>{{Cite web |last=Johnson |first=Scott K. |date=25 July 2013 |title=Gibraltar might be the beginning of the end for the Atlantic Ocean |url=https://arstechnica.com/science/2013/07/gibraltar-might-be-the-beginning-of-the-end-for-the-atlantic-ocean/ |access-date=18 March 2021 |website=Ars Technica |archive-date=20 June 2021 |archive-url=https://web.archive.org/web/20210620015430/https://arstechnica.com/science/2013/07/gibraltar-might-be-the-beginning-of-the-end-for-the-atlantic-ocean/ |url-status=live }}</ref> but on geological rather than human timescales.