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Miocene to Quaternary alkali basalts in the Lut–Sistan region, eastern Iran are spatially associated with two active, N–S-trending dextral strike–slip fault systems in the region, i.e., the Neh faults in the Sistan suture zone and the Nayband fault ~200km further to the west in the Lut block. Here, we present new ⁴⁰Ar/³⁹Ar ages, geochemical and Sr–Nd isotopic data for these rocks to decipher the petrogenetic processes responsible for their formation and regional tectonic implications. Our new ages indicate that the volcanism commenced at ~14Ma in the western Lut region and ~11Ma in the northern Sistan suture zone. The rocks are composed dominantly of hawaiites and mugearites with minor basanites and basaltic andesites. Petrographic observations and major and trace elemental variations suggest that the alkali basalts underwent variable fractionation of olivine, clinopyroxene and Fe–Ti oxides. Chondrite …