Editing Shield volcano (section)

=== Iceland ===
[[File:Skjaldbreidur Herbst 2004.jpg|thumb|right|[[Skjaldbreiður]] is a shield volcano in [[Iceland]], whose name means ''broad shield'' in Icelandic.]]

Located over the [[Mid-Atlantic Ridge]], a [[Divergent boundary|divergent]] [[plate tectonics|tectonic plate]] boundary in the middle of the Atlantic Ocean, Iceland is the site of about 130 volcanoes of various types.<ref name=worldbook /> Icelandic shield volcanoes are generally of [[Holocene]] age, between 5,000 and 10,000 years old. The volcanoes are also very narrow in distribution, occurring in two bands in the West and North Volcanic Zones. Like Hawaiian volcanoes, their formation initially begins with several eruptive centers before centralizing and concentrating at a single point. The main shield then forms, burying the smaller ones formed by the early eruptions with its lava.<ref name=uog/>

Icelandic shields are mostly small (~{{convert|15|km3|cumi|0|abbr=on}}), symmetrical (although this can be affected by surface topography), and characterized by eruptions from summit calderas.<ref name=uog>{{cite web|title=Holocene shield volcanoes in Iceland|url=http://geoleoedocs.sub.uni-goettingen.de:8080/dspace/bitstream/gledocs-108/1/Andrews%2BGudmundsson.pdf|publisher=University of Göttingen|access-date=21 February 2011|author1=Ruth Andrews|author2=Agust Gudmundsson|name-list-style=amp|year=2006|url-status=dead|archive-url=https://web.archive.org/web/20070611035239/http://geoleoedocs.sub.uni-goettingen.de:8080/dspace/bitstream/gledocs-108/1/Andrews%2BGudmundsson.pdf|archive-date=11 June 2007}}</ref> They are composed of either [[Tholeiitic magma series|tholeiitic]] [[olivine]] or [[Picrite basalt|picritic basalt]]. The tholeiitic shields tend to be wider and shallower than the picritic shields.<ref name=1996-iceland>{{cite journal|last=Rossi|first=M. J.|title=Morphology and mechanism of eruption of postglacial shield volcanoes in Iceland|journal=[[Bulletin of Volcanology]]|year=1996|volume=57|issue=7|pages=530–540|doi=10.1007/BF00304437|bibcode=1996BVol...57..530R|s2cid=129027679}}</ref> They do not follow the pattern of caldera growth and destruction that other shield volcanoes do; caldera may form, but they generally do not disappear.<ref name=hvw-shield /><ref name="uog" />