The Pan-African Damara orogen of Namibia is characterized by large-scale granitoid intrusions. Two plutons in the Northern Central Zone (NCZ) of the Damara orogen within the Okombahe district have U-Pb zircon ages of 576.2 +/- 5.7 Ma and 570.9 +/- 4.9 Ma that predate the time of high grade regional metamorphism which occurred between 540 and 480 Ma. The intrusive rocks are magnesian high-K alkali-calcic granodiorites to granites, are enriched in HFSE and REE, and have undergone only a limited degree of fractional crystallization, and do not contain xenoliths of local country rocks. Initial isotope compositions are unevolved with Sr-87/Sr-86 between 0.704 and 0.706 and initial epsilon Nd ranging from -1.9 to -3.9. Lead isotopes are radiogenic (Pb-206/Pb-204: 18.32 to 18.61, Pb-207/Pb-204: 15.61 to 15.69 and Pb-208/Pb-204: 37.87 to 39.29) with variable Pb-207/Pb-204 ratios at almost constant Pb-206/Pb-204 and Pb-208/Pb-204 ratios, suggesting a derivation from ancient sources with comparatively high U/Pb but low Th/Pb ratios. The limited variations in Sr, Nd and Pb isotopes were not caused by crustal contamination or magma mixing, but instead reflect source heterogeneities. Strontium and Nd isotope compositions suggest mafic lithologies similar to amphibolites from the Kalahari Craton basement as potential sources. A comparison with amphibolite melting experiments confirms the possible derivation of the granodiorites from an amphibolitic source. Calculated maximum zircon saturation temperatures at insignificant amounts of inherited zircon, indicate intrusion temperatures of up to 900 degrees C Apatite saturation temperatures are higher, up to ca. 950 degrees C. Pressures of 5 to 10 kbar are determined through Qz-Ab-Or systematics and are interpreted as minimum pressures at the site of melting suggesting that the granodiorites/granites represent high temperature partial melts generated in the lower crust. Although there are some compositional similarities with granites generated in subduction zones, radiogenic Pb isotope ratios and high delta O-18 values suggest that reprocessed amphibolitic rocks are more likely sources. (C) 2014 Elsevier B.V. All rights reserved.