A REVIEW ON ADAKITE

Adakite was proposed over a decade ago. It is a kind of acid-intermediate and calc-alkaline igneous rock, with the stickup characteristics of SiO₂ ≥ 56%, Al₂O₃ ≥ 15%, relatively depletive HREE and Y(Y ≤ 18×10^-6, Yb ≤ 1. 9×10^-6), high Sr(> 400×10^-6), La/Yb and Sr/Y, as well as positive Sr anomaly but absent or slightly negative Eu anomaly. There are two types of adakites with different petrogenesis:one is formed by the melting of subducting young(≤ 25-30 Ma) slab, and the other is formed by the partially melting of basaltic lower crust under the continental accretion setting. Adakites are important indicators of ore deposits.