Experiments in the quartz-saturated part of the system KFMASH under fO(2) conditions of the haematite-magnetite buffer and using bulk compositions with X-Mg of 0.81, 0.72, 0.53 define the stability limits of several mineral assemblages within the P-T field 9-12 kbar, 850-1100degreesC. The stability limits of the mineral assemblages orthopyroxene+spinel+cordierite+/-sapphirine, orthopyroxene+garnet+sapphirine, sapphirine+cordierite+orthopyroxene and garnet+orthopyroxene+ spinel have been delineated on the basis of P-T and T-X pseudosections. Sapphirine did not appear in the bulk composition of X-Mg=0.53. A partial petrogenetic grid applicable to high Mg-Al granulites metamorphosed at high fO(2), developed in our earlier work, was extended to higher pressures. The experimental results were successfully applied to several high-grade terranes to estimate P-T conditions and retrograde P-T trajectories.