Fig. 2

Evolution of Zr in the different magmatic systems. a Zr versus MgO diagram. Data source in addition to own data: Venturelli et al. (1984); Bigioggero et al. (1994); Callegari et al. (2004); Owen (2008); Conticelli et al. (2009). b Zr versus M-value [M = (K + Na + 2 × Ca)/Al × Si]. In addition the Zr solubility calculated with the equation of Watson and Harrison (1983) is shown. Bold arrow in the lower part indicate general, calc-alkaline evolutions