This study presents a comprehensive account of the petrogenetic and geodynamic evolution of the Bellara Trap volcanic rocks from the Ingaldhal Formation, Chitradurga Group, western Dharwar Cra-ton (WDC). Geochemical attributes of these rocks are consistent with two groups with distinct evolutionary trends: one comprising tholeiitic, MORB (mid-ocean ridge basalt) type basalts (BTB) and the other corre-sponding to calc-alkaline andesites (BTA). Basalts are essentially composed of clinopyroxene and plagio-clase whereas the andesites are porphyritic with phenocrysts of plagioclase, clinopyroxene and polycrystal-line quartz embedded in a groundmass of K-feldspar, quartz and opaques. Primary igneous mineralogy is overprinted by greenschist facies metamorphism resulting in chlorite-actinolite-plagioclase assemblage. The BTB samples reflect nearly flat REE patterns with weak LREE enrichment in contrast to pronounced LREE enhancement over HREE discernible for BTA. Tectonically, the BTB samples correspond to an ac-tive mid-oceanic ridge-rift setting with a MORB composition, whereas a back-arc basin (BAB) regime is corroborated for the BTA samples fractionating from back-arc basin basalts. Geochemical imprints of subduction input are more pronounced in BTA compared to BTB as mirrored by their elevated abundances of incompatible fluid mobile elements like Ba, Th, U and LREE. The BTB is endowed with an N- to E-MORB signature attributable to minor contributions from subduction-related components at the incep-tion of a back-arc basin in the vicinity of an active subduction system. The BTA derived through differentia-tion of a basaltic magma with BABB (back-arc basin basalt) affinity compositionally akin to a heterogene-ous source mantle carrying depleted MORB-type and enriched arc-type components inducted with pro-gressive subduction. The BABB-type andesites and MORB-type basalts from Bellara Traps record a com-positional heterogeneity of mantle in an intraoceanic arc-back arc system. Mantle processes invoke a BABB-MORB spectrum with a MORB-like endmember and an arc-like endmember associated with a ju-venile back-arc basin. This study infers a Neoarchean analogue of Mariana-type back-arc rift setting proximal to the arc with a gradual transition from anhydrous to hydrous melting processes synchronized with MORB-mantle and arc-mantle interaction during initiation of a nascent back arc adjacent to the arc. The MORB-BABB compositional spectrum for the Bellara Traps conforms to a Neoarchean back-arc basin that evolved under an extensional tectonic regime associated with incipient stages of back-arc rifting and incorporation of subduction-derived components in the mantle output. This study complies with Neoar-chean intraoceanic accretionary cycle plate tectonics in WDC.