Fig. 14

Tectonic discrimination diagrams of (a) K2O/Na2O vs. SiO2/Al2O3; (b) Fe2O3 + MgO vs. TiO2; (c) SiO2 vs. K2O/Na2O; (d) Fe2O3 + MgO vs. Al2O3/SiO2. Fields are after Bhatia60 PM-passive margin, ACM-active continental margin, CIA-continental island arc, OIA-oceanic island arc.