and has also formed on the Moon, Mars, Venus, and the asteroid Vesta.The crustal portions of oceanic tectonic plates are composed predominantly of basalt, produced from upwelling mantle below, the ocean ridges.
These phenocrysts usually are of olivine or a calcium-rich plagioclase, which have the highest melting temperatures of the typical minerals that can crystallize from the melt.
is a common extrusive igneous (volcanic) rock formed from the rapid cooling of basaltic lava exposed at or very near the surface of a planet or moon.
Flood basalt describes the formation in a series of lava basalt flows.
In particular, the relative abundance of europium compared to the other REE is often markedly higher or lower, and called the europium anomaly.
It arises because Eu in plagioclase feldspar, unlike any of the other lanthanides, which tend to only form 3 cations.