Basalt (US: /bəˈsɔːlt, ˈbeɪsɒlt/, UK: /ˈbæsɔːlt, ˈbæsəlt/)[1][2][3][4] is a mafic extrusive igneous rock formed from the rapid cooling of lava rich in magnesium and iron[5] exposed at or very near the surface of a terrestrial planet or a moon.[6] More than 90% of all volcanic rock on Earth is basalt,[7] and the eruption of basalt lava is observed by geologists at about 20 volcanoes per year.[8]
Answers & Comments
Answer:
Basalt (US: /bəˈsɔːlt, ˈbeɪsɒlt/, UK: /ˈbæsɔːlt, ˈbæsəlt/)[1][2][3][4] is a mafic extrusive igneous rock formed from the rapid cooling of lava rich in magnesium and iron[5] exposed at or very near the surface of a terrestrial planet or a moon.[6] More than 90% of all volcanic rock on Earth is basalt,[7] and the eruption of basalt lava is observed by geologists at about 20 volcanoes per year.[8]