Fluid-present melting of meta-igneous rocks and the generation of leucogranites – Constraints from garnet major and trace element data, Lu-Hf whole rock-garnet ages and whole rock Nd-Sr-Hf-O isotope data

Pan-African high-grade metamorphism in the Proterozoic Damara orogen (Namibia) led to formation of garnet-bearing leucosomes in potassic meta-igneous gneisses producing a meta-igneous migmatite. In addition, the migmatite (gneiss (mesosome) plus leucosome) was intruded by small-scale leucogranitic melts with a high amount of accumulated biotite and garnet. U-Pb zircon ages obtained on the mesosome and the leucosome indicate late Proterozoic (ca. 850 Ma) concordia upper intercept ages which are interpreted as minimum ages of the precursor rock of the migmatite. U-Pb monazite ages obtained on the leucogranite give a concordant age of 512±1 Ma and two reversely discordant ages wit