Basalt
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Basalt; US: buh-SALT is an aphanitic extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron exposed at or very near the surface of a rocky planet or moon
Basalt 12
QAPF diagram with basalt/andesite field highlighted in yellow. Basalt is distinguished from andesite by SiO2 < 52%.
Vesicular basalt at Sunset Crater, Arizona. US quarter (24mm) for scale.
Columnar basalt flows in Yellowstone National Park, US
Igneous rock
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Igneous rock, or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava.
Basalt
…Basalt (UK: BAH-salt); US: buh-SALT) is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or…
Volcanic eruptions of lava are major sources of igneous rocks. (Mayon volcano in the Philippines, erupting in 2009)
Natural columns of igneous rock separated from each other by columnar joints, in Madeira
Formation of igneous rock
Extrusive igneous rock is made from lava released by volcanoes