Geological Magazine. 103 (2): 110-114. Bibcode:1966GeoM..103..110S
More than 90% of all volcanic rock on Earth is basalt. Rapid-cooling, fine-grained basalt has the same chemical composition and mineralogy as slow-cooling, coarse-grained gabbro. The eruption of basalt lava is observed by geologists at about 20 volcanoes per year. […]