Adakite

Adakite is a petrologic term for a volcanic or intrusive igneous rock that forms by melting of a subducting slab of oceanic crust basalt. Adakites include a range of resulting rock types and are specifically defined chemically by high Sr/Y and La/Yb ratios and low Y and Yb trace element content.^[1] There is some debate as to the process that produces adakites. Low magnesium adakites may be representative of relatively pure partial melting of a subducting basalt, whereas high magnesium adakite or high magnesium andesites may represent melt contamination with the peridotites of the overlying mantle wedge.^[2]

References

1. ^ http://www.dur.ac.uk/yaoling.niu/MyReprints-pdf/PRCastillo-adakite.pdf Paterno R. Castillo, An overview of adakite petrogenesis, Chinese Science Bulletin 2006 Vol. 51 No. 3 257—268
2. ^ http://www.the-conference.com/JConfAbs/1/497.html R. P. Rapp and N. Shimizu, Arc Magmatism in Hot Subduction Zones: Interactions Between Slab-Derived Melts and the Mantle Wedge, and the Petrogenesis of Adakites and High-Magnesian Andesites (HMA)