Abstarct: This research investigates the petrogenesis and geochemistry of volcanic lavas in the Lavarab area, with a focus on petrographic characteristics, geochemical and mineral chemistry features, geochronology, and their origin and source in eastern Iran. These lavas are located in the southern part of the Sefidabeh fore-arc basin within the Sistan suture zone. Their compositions are mostly basic, and include basanite, alkali basalt, and trachybasalt. They belong to the sodic alkaline type. The lavas display massive and sometimes vesicular structures, with porphyritic textures dominated by microlitic to glassy groundmass. The main phenocrysts are clinopyroxene, olivine, and occasionally analcime. baxsed on mineral chemistry, olivines are mainly forsterite, chrysolite, and hyalosiderite, while clinopyroxenes exhibit diopside and augite compositions, belonging to peralkaline to subalkaline magma series. Single-clinopyroxene thermobarometry indicates Cpx crystallization temperatures between ~1110 and 1260 °C, and pressures ranging from 0.05 to 1.35 GPa, equivalent to depths of ~2–51 km under high oxygen fugacity conditions in both the upper and lower continental crust. Olivine–liquid thermometry yields crystallization temperatures of ~1385–1393 °C for basanites and ~1275–1339 °C for alkali basalts in pressure of 1.4 GPs. The oscillatory composition changes from core to rim of phenocrysts in the studied basalts provide evidence of magma recharge through multiphase injections of fresh magma into the reservoir(s) prior to volcanic eruptions. Petrographic features such as resorption, crystal rounding, patchy zoning in olivine, and sieve textures in clinopyroxenes support this subject. U–Pb zircon dating yielded ages of 24.19 ± 0.21 Ma and 9.63 ± 0.2 Ma, implying at least two stages of volcanic activity in late Oligocene and late Miocene. The Lavarab lavas show enrichment of LREE relative to HREE and lack a negative Eu anomaly. They display negative Nb and Ti anomalies and positive anomalies in Pb, Sr, P, and U. Their Mg# values (73–83%) indicate a primitive parental magma. The parental magma was derived from an enriched mantle source and produced by 1–5% partial melting of a garnet–spinel lherzolite source, sometimes with garnet dominance and at other times spinel dominance, indicating the alkaline and non-fractionated nature of the parental magma. According to tectonic discrimination diagrams baxsed on whole-rock and clinopyroxene chemistry indicate WPA and VBA settings. Considering the subduction- and collision-related tectonic regime in eastern Iran, the Lavarab alkaline basalts are interpreted as post-collisional magmas, likely generated by asthenospheric upwelling following lithospheric thinning during the Neogene. baxsement-involved N–S trending faults in the region (Zahedan and Harriroud) played a significant role in the ascent and eruption of the parental magmas.