Fig. 10

a Zr-Ti-Y diagram with fields for basaltic rocks from Pearce and Cann (1973). WPB within plate basalts, IAT island arc tholeites, MORB mid-ocean ridge basalt, CAB continental margin arc basalts. ZSU meta-basalt from Pfeifer et al. (1989): pink symbol 2 analyses from Table 2, ZSU Zermatt data from Fig. 5, ZSU & Combin Saas data from Fig. 5. Global MORB from Arevalo and McDonough (2010). b Nb-Zr-Y discrimination diagram (after Meschede, 1986). WPAB within plate alkali basalt, WPTB within plate tholeitic basalt, E-MORB enriched mid-ocean ridge basalt, N-NORB normal mid-ocean ridge basalt, IAB island arc basalt