A multistage petrogenesis is proposed for banded metabasaltic amphibolite and tonalite tectonically interlayered on a fine (centimetre) scale within upper and lower amphibolite sequences of the Harts Range meta-igneous complex, eastern Arunta Block, central Australia. The basaltic amphibolites exhibit only slight rare earth element (REE) fractionation ( Ce N Yb N = 2.5 ) and can be related by plagioclase + clinopyroxene — dominated low-pressure fractional crystallisation in the tholeiitic trend. Early olivine removal from a moderately aluminous, trace element impoverished tholeiitic picrite parent magma caused significant Ni depletion in the evolved residual liquids that gave rise to the basaltic amphibolites. The primary picritic melt was generated by high degrees (> 30%) of hydrous partial melting of a depleted mantle source selectively re-enriched in large-ion lithophile (LIL) elements. Chondrite normalised REE patterns for low-Al 2O 3 tonalitic layers within the basaltic amphibolite units are moderately fractionated ( Ce N Yb N = 3.3–7.3 ) and show significant negative Eu anomalies. REE modelling indicates that the precursors to the tonalitic rocks could have been generated by small degrees (≈ 10%) of partial melting of a light rare earth element (LREE) enriched basaltic parent with plagioclase, clinopyroxene and minor hornblende comprising coexisting residual phases. Melting at relatively low P H 2O (< 0.5 kbar) and depths between 20 and 30 km is indicated. The amphibolite sequence is interpreted as a complexly folded and metamorphosed bimodal basalt-tonalite suite formed at an early Proterozoic rifted continental margin or intra-cratonic rift.