Changes

[[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.

[[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.

== Sources ==

== Sources ==

[http://volcanoes.usgs.gov/Products/Pglossary/basalt.html USGS Photo Glossary]

[http://volcanoes.usgs.gov/Products/Pglossary/basalt.html USGS Photo Glossary]

[[Category:Igneous rocks]]

[[Category:Igneous Rocks]]