Chemical variation, modal composition and classification of granitoids

pdf file. Same as Figure 11 of main text, using SiO2–α diagram. α is defined as α = (Al – Na – K)/Ca, in atomic proportions, i.e. the parameter such that Al = αCa + Na + K. Thus, A/CNK = 1 corresponds to α = 2, and A/NK = 1 to α = 0 (see main text)