Short post about the thin section of biotite-kyanite carbonaceous schist from Keivy, Kola peninsula, Russia. The rock was invloved in processes of muscovitization, staurolitization, alteration, retrogressive metamorphism etc. I would like to show several pictures of Al2[SiO4]O modifications and high aluminous phases.
|Fig. 2. The same field, PPL.|
|Fig. 3. Staurolitization. Staurolite replaces kyanite crystal. PPL.|
Fig. 4. Fibrous sillimanite aggregate, muscovitization and chloritization of biotite. PPL.
The pictures show complex and multi-step process of metamorphism of highly aluminous metasediments.