玄武岩形成
是由火山噴發出的岩漿冷卻後凝固而成的一種致密狀或泡沫狀結構的岩石。它在地質學的岩石分類中,屬於岩漿岩(也叫火成岩)。火山爆發流出的岩漿溫度高達攝氏一千二百度,因有一定的粘度,在地勢平緩時,岩漿流動很慢,每分鍾隻流動幾米遠;遇到陡坡時,速度便大大加快。它在流動過程中,攜帶著大量水蒸汽和氣泡,冷卻後,便形成了各種變異的形狀
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