A Geochemical Classification for Granitic Rocks

This geochemical classification of granitic rocks is based upon three INTRODUCTION variables. These are FeO/(FeO + MgO) = Fe-number [or Although granitoids are the most abundant rock types FeO tot /(FeO tot + MgO) = Fe * ], the modified alkali-lime index in the continental crust, no single classification scheme (MALI) (Na 2 O + K 2 O -CaO) and the aluminum saturation has achieved widespread use. Part of the problem in index