Some results of the geological mapping of the southern-central part of the Ana-Sira-Massif are presented. The Ana-Sira-Massif belongs to the massif anorthosites and is characterized by its numerous and manifold Fe-Ti ores. The Ana-Sira-Massif shows a layered composition, resulting from its rock sequence and structure. Cumulate textures, graded bedding, rhythmic layering, igneous lamination, cross-bedding, slumping and the whole structure of the mass, argue for a synkinematic, magmatic origin through fractional crystallization under the influence of convection currents. The ilmenite ores are probably the products of the oxide-rich residual melt after the formation of the main part of the anorthositic rocks.