This work aims at the understanding of the petrogenesis of Kibarian metamorphic formations in the West part of Lake Kivu. Here are presented detailed petrographic study of Miowe and Bulambika gneisses at Bunyakiri, new geochemical data of major elements and a large-scale geological map of the study area. The macroscopic petrographic study has distinguished in Miowe and Bulambika gneiss two lithological facies: the augen gneiss and the granitic gneiss. Veins and pegmatite pockets are observed in these gneisses. The geochemical study on basis of major elements revealed that these gneisses derived from a metamorphic evolution of granites and granodiorites of calc-alkaline series. They are therefore formed in a geodynamic context of subduction.