Difference between revisions 106871684 and 106871685 on dewiki

[[ImagFile:seacaving.jpg|thumb|300px|Exploring a sea cave]]
A '''sea cave''', also known as a '''littoral cave''', is a type of [[cave]] formed primarily by the [[wave]] action of the [[sea]].  The primary process involved is erosion.  Sea caves are found throughout the world, actively forming along present coastlines and as [[relict]] sea caves on former coastlines. Some of the largest wave-cut caves in the world are found on the coast of Norway, but are n(contracted; show full)water, imparted by light passing through openings underwater. The Romans built a stairway in its rear and a now-collapsed tunnel to the surface. The Greek islands are also noted for the variety and beauty of their sea caves. Numerous sea caves have been [[Speleology#Cave cartography|surveyed]] in England, Scotland, and in France, particularly on the Normandy coast. The largest sea caves are found along the west coast of the United States, the Hawaiian islands, and the Shetland Islands. 

== Formation ==
[[
ImagFile:seacave fault.jpg|thumb|left|250px|Sea cave formation along a fault]]
[[ImagFile:seacave dike.jpg|thumb|right|250px|Sea cave formation along a dike]]
[[ImagFile:littoral sinkhole.jpg|thumb|left|250px|Sea cave collapse]]
[[ImagFile:Belvedere della Grotta di Nereo.jpg|thumb|left|250px| The "belvedere" watching place in the north [[Sardinia]] [[Nereo Cave]]]]
[[File:Akun Island basalt sea cave.jpg|thumb|right|[[Akun Island]] [[basalt]] sea cave]]
Littoral caves may be found in a wide variety of host rocks, ranging from [[sedimentary]] to [[Metamorphic rock|metamorphic]] to [[igneous]], but caves in the latter tend to be larger due to the greater strength of the host rock. 

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Life within sea caves may assist in their enlargement as well. For example, [[sea urchins]] drill their way into the rock, and over successive generations may remove considerable bedrock from the floors and lower walls. You might not find a big variety of fishes.

== Factors influencing size ==
[[
ImagFile:seacave cathedral.jpg|thumb|250px|Some sea caves empty out at low tide]]
Most sea caves are small in relation to other cave types. A current compilation of sea-cave surveys [http://www.caverbob.com/seacave.html Long sea caves of the world] shows three over 300 meters, 15 over 200 meters, and 85 over 100 meters in length. In Norway, several apparently relict sea caves exceed 300 meters in length. There is no doubt that many other large sea caves exist but have not been investigated due to their remote locations and/or hostile sea conditions. 

Several factors contribute to the development of relatively large sea caves. The nature of the zone of weakness itself is surely a factor, although difficult to quantify. A more readily observed factor is the situation of the cave’s entrance relative to prevailing sea conditions. At [[Santa Cruz Island]], the largest caves face into the prevailing northwest swell conditions—a factor which also makes them more difficult to survey. Caves in well-protected bays sheltered from prevailing seas and winds tend to be smaller, as are caves in areas where the seas tend to be calmer. 

The type of host rock is important as well. All of the largest sea caves are in [[basalt]],{{FactCitation needed|date=October 2007}} a strong host rock compared to sedimentary rock. Basaltic caves can penetrate far into cliffs where most of the surface erodes relatively slowly. In weaker rock, erosion along a weaker zone may not greatly outstrip that of the cliff face. 

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== References ==

*{{cite book |author=Bunnell, D. |title=Sea Caves of Santa Cruz Island |publisher=McNally and Loftin |location=Santa Barbara, CA |year=1988 }}
*{{cite book |author=Bunnell, D. |title=Sea Caves of Anacapa Island |publisher=McNally and Loftin |location=Santa Barbara, CA |year=1993 }}
*{{cite book |author=Bunnell, D. |chapter=Littoral Caves |editor=Gunn, J. |title=Encyclopedia of Caves and Karst |publisher=Fitzroy Dearborn |location=New York |year=2004 |isbn=1
-57958-399-7}}
*{{cite book |author=Hansom J.D. |chapter=Papa Stour, Shetland |editor=May, V.J., Hansom, J.D. |title=Coastal Geomorphology of Great Britain |publisher=Joint Nature Conservancy Committee, UK |year=2003 |series=Geological Conservation Review Series |volume=28}}
*{{cite journal |author=Moore, D.G. |title=Origin and development of sea caves |journal=National Speleological Society Bulletin |volume=16 |issue= |pages=71–76 |year=1954 }}
*{{cite journal |author=Sjöberg, Rabbe |title=Coastal Caves Indicating Preglacial Morphology in Norway |journal=Cave Science, The Transactions of the British Cave Research Association |volume=15 |issue=3 |pages=99–103 |year=1988 }}

== External links ==
{{Commonscat|Sea caves}}
* [http://www.goodearthgraphics.com/virtcave/seacaves/seacaves.html Photos and information] on sea caves in the Virtual Cave

{{Caves}}
{{coastal geography}}

[[Category:Sea caves| ]]
[[Category:Coastal and oceanic landforms]]

[[ko:해식동]]
[[ja:海蝕洞]]
[[simple:Sea caves]]
[[sk:Príbojová jaskyňa]]