Figure 7. AFM diagrams for high-grade schists and gneisses. FeO value of biotite has been calculated using the method proposed by Dymek (1983). Open squares represents St, Grt, and Crd compositions. Black squares represent Bt compositions. A. M1 mineral association (Grt-St-Sil-Bt-Ms with Bt and Ms enclosed in Grt); gray squares represent the composition of some Al-silicate (Als) Bt-bearing schists (Spadea and Prosser, Chap. 28, this volume). B. M2 mineral association (Grt-Sil-Bt-Kfs with matrix Bt) plotted together with Als-Bt-bearing schists. C. Minerals and bulk-rock composition (gray squares) from Crd-Bt-Kfs-Sil-And-bearing migmatitic gneisses.

Figure 7. AFM diagrams for high-grade schists and gneisses. FeO value of biotite has been calculated using the method proposed by Dymek (1983). Open squares represents St, Grt, and Crd compositions. Black squares represent Bt compositions. A. M₁ mineral association (Grt-St-Sil-Bt-Ms with Bt and Ms enclosed in Grt); gray squares represent the composition of some Al-silicate (Als) Bt-bearing schists (Spadea and Prosser, Chap. 28, this volume). B. M₂ mineral association (Grt-Sil-Bt-Kfs with matrix Bt) plotted together with Als-Bt-bearing schists. C. Minerals and bulk-rock composition (gray squares) from Crd-Bt-Kfs-Sil-And-bearing migmatitic gneisses.