Neoproterozoic pre- and post-deformational metamorphism in the Western Domain of the Karagwe-Ankole Belt reconstructed by Lu-Hf garnet geochronology in the Kibuye-Gatumba area, Rwanda

Abstract The timing of metamorphism in the Karagwe-Ankole Belt (KAB, Central Africa) has never been investigated in detail. Although its metamorphic history and geochronology would provide a unique and crucial contribution, these aspects have largely been overlooked in most published geodynamic reconstructions of this belt. In this study, well-constrained Lu-Hf garnet dates obtained on four samples (three metasiltstones, one schist) can be directly linked to pre- and post-deformational greenschist metamorphism and broadly constrain the timing of Neoproterozoic deformation in the Karagwe-Ankole Belt. Depending on the host rock composition, garnet porphyroblasts grew over intervals of 620 Ma).