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[[Image:Basalt.jpg|thumb|300px|Basalt lava (glowing rock) oozes over basalt lava flow]]'''Basalt''' is a hard, black [[volcanic rock]] with less than about 52 weight percent [[silica]] (<math>SiO_2</math>). Because of basalt's low silica content, it has a low [[viscosity]] (resistance to flow). Therefore, basaltic lava can flow quickly and easily move more than 20 km from a [[vent]]. The low viscosity typically allows [[volcanic gas]]es to escape without generating enormous eruption columns. Basaltic lava fountains and fissure eruptions, however, still form explosive fountains hundreds of meters tall. Common minerals in basalt include [[olivine]], [[pyroxene]], and [[plagioclase]]. Basalt is erupted at temperatures between 1100 to 1250° C and is the most widely distributed rock in the world.<ref name="Living Earth">{{cite book |title=Living Earth: Outline of the Geology of Iceland |author=Ari Trausti Gudmundsson, Halldor Kjartansson |publisher=Mág o menning |place=Reykjavík |year=2007, 2015 |chapter= The Foundation: Mostly Basalt |page=28 |isbn=978-9979-3-3360-9}}</ref>  

[[Image:Basalt.jpg|thumb|300px|Basalt lava (glowing rock) oozes over basalt lava flow]]'''Basalt''' is a hard, black [[volcanic rock]] with less than about 52 weight percent [[silica]] (<math>SiO_2</math>). Because of basalt's low silica content, it has a low [[viscosity]] (resistance to flow). Therefore, basaltic lava can flow quickly and easily move more than 20 km from a [[vent]]. The low viscosity typically allows [[volcanic gas]]es to escape without generating enormous eruption columns. Basaltic lava fountains and fissure eruptions, however, still form explosive fountains hundreds of meters tall. Common minerals in basalt include [[olivine]], [[pyroxene]], and [[plagioclase]]. Basalt is erupted at temperatures between 1100 and 1250° C and is the most widely distributed rock in the world.<ref name="Living Earth">{{cite book |title=Living Earth: Outline of the Geology of Iceland |author=Ari Trausti Gudmundsson, Halldor Kjartansson |publisher=Mág o menning |place=Reykjavík |year=2007, 2015 |chapter= The Foundation: Mostly Basalt |page=28 |isbn=978-9979-3-3360-9}}</ref>