basalt is the main composition of lava rocks that cool from magma,, Liquid that rises  from the deep earth at volcanoes.

Basalt is the result of melting meteoritic material, so it forms on other planets as well as earth, making it the “mother liquor” of terrestrial planets. It is found all over earth, but especially under the oceans and in other areas where earth’s crust is thin. It formed here because of the great rift, which tore rodinia apart 1096 million years ago. Most of earth’s surface is basalt lava, but BASALT MAKES UP only a small fraction of continents. 

Today basalt is forming at many active rifts, including Iceland, The great rift valley in Africa, the Red sea and the rio grande valley of new mexico.