The middle to late Proterozoic Awasib Mountain terrain (AMT) straddles the boundary between the Rehoboth and Gordonia subprovinces in southern Namibia. The AMT is made up of two major crustal components, the older of which is correlated with the Namaqualand Metamorphic Complex (NMC), and the younger with the Sinclair Sequence. The oldest part of the early-stage crust is represented by the amphibolite-grade Kairab Complex which has undergone three episodes of deformation (D1-D3). Within this complex, high-alumina pillow-bearing basalts form part of a bimodal volcanic succession and yield an age of ca. 1460 Ma (Rb-Sr, Pb-Pb) with a low 87Sr/86Sr initial ratio (R0) of 0.7027 ± 1. While these basalts are characterised by the low contents of Ti, Nb, Zr, Y, Ni and Cr typical of island-arc or back-arc settings, low- and high-silica rhyolites display chondrite-normalised patterns (especially negative Th anomalies) which are also consistent with a subduction-related environment. Younger metaluminous granitoids and gabbroids in the early-stage crust have undergone D3 deformation and low-medium grade metamorphism. There is a close spatial and compositional association between the metavolcanic succession and these younger intrusive rocks. The association between gabbro, a maic dyke swarm, pillow-bearing basalt, pyroclastic rhyolite and tonalite-trondhjemite resembles that of a dismembered ophiolite complex. Progressive intrusion of tonalite (Aunis Tonalite Gneiss; age 1271 ± 62 Ma, R0 = 0.7029 ± 3) to granite (Khorasib Granite Gneiss) relects juvenile magma input followed by an increasing contribution from subcontinental within-plate mantle lithosphere and heterogeneous crust. Ocean-ridge granite (ORG)-normalised trace element patterns for the granitoid gneisses are typical of arc granites (i.e. enrichment in K, Rb, Ba and Th relative to Nb, Zr and Y) and suggest that the change in granitoid compositions records a progression from a primitive to mature (continental) arc or post-orogenic environment.