Evolution of the Palaeoproterozoic Rehoboth Sequence within the Rehoboth Basement Inlier of Namibia probably documents transition from arc to back arc regions within an Eburnian magmatic arc. New field evidence suggests a stratigraphic position of the arc-related Gaub Valley Formation in the lower portion of the Rehoboth Sequence. This is overlain by the shallow marine back-arc related Elim Formation. Sedimentation was accompanied by mafic hyaloclastic volcanism. Geochemical analyses of these volcanics reveal their subalkaline, tholeiitic nature as well as local strong alteration by hydrothermal or metamorphic overprinting. REE-patterns remain unaffected and exhibit depletion of HREE, relatively to MORB, while LREE are slightly enriched. Pronounced negative spikes of Zr and Hf, minor to no depletion of Nb, Ti and Ta as well as normal enrichment of LILE are in accordance with modern back arc basalts in areas with minor subduction influence. The Gaub Valley Formation and basal Elim Formation were intruded by calc-alkaline, subduction-related dioritic to tonalitic magmas, the Naub and Weener plutons. Close spatial and temporal linkage must be assumed between the Elim and Gaub Valley Formations, as well as a rapid change from subduction zone to back arc magmatism. Alternatively, different source regions may have been active at the same time. Subsequently, the Elim Formation was intruded by the ultramafic to mafic layered Alberta Complex. Cumulate layers of plagioclase, olivine and pyroxene predominate within the interior of this body. However, gabbroic rocks from the Marginal Zone display affinity to mafic volcanics of the Elim Formation, which may be due either to AFC processes or to an origin from the same source. Modelling, based on fractional crystallisation, shows that rocks of the Alberta Complex can be genetically linked to the volcanic rocks of the Elim Formation by extracting varying amounts of ol, opx, cpx and plag and mixing them with minor amounts of fractionated liquid.