U-Pb zircon ages and Rb-Sr whole rock ages have been obtained for several intrusive and volcanic rocks of the Rehoboth Sequence (Weener Igneous Complex, WIC and Gaub Valley Formation, GVF) and the pre-Rehoboth basement (Mooirivier Complex) in the Nauchas area of Namibia. U-Pb zircon upper discordia intercepts define similar ages for the WIC (~1765 and ~1767 Ma), associated granitoids (~1762 Ma and ~1743 Ma), as well as for the pre-Rehoboth Mooirivier Complex (~1725 Ma) and the Neuhof (Kamasis) Formation (~1784 Ma; Burger and Walraven, 1978). These data suggest that the Rehoboth Sequence and the pre-Rehoboth basement are broadly coeval. Rb-Sr whole rock data define errorchrons of ~1752 Ma with an initial 87Sr/86Sr ratio of 0.7034 for the GVF and of ~1620 Ma with an initial ratio of 0.7047 for the WIC. An intense disturbance of this isotopic system during post-emplacement alteration processes is inferred. In a regional context, comparable ages have been determined in crustal segments extending from southern Brazil through southern Africa to equatorial Africa and constitute a major crust-forming event during late Paleoproterozoic times (Eburnian-Ubendian cycle). Similarities in age and rock association of other inliers in Namibia (i.e. Epupa and Huab Inlier, Abbabis Inlier, Namaqua Metamorphic Complex) suggest that much of the pre-Damara basement was formed during this event, in magmatic arc settings.