The volcanic and subvolcanic rocks of North Zahklut, located in the Dehaj–Sarduieh magmatic belt of the southeastern Urumieh–Bazman arc, represent subduction-related magmatism in southeastern Iran. This study integrates petrography, whole-rock major and trace element geochemistry, and rare earth element (REE) modeling to constrain the magma source, melting conditions, and petrogenetic evolution of the andesitic and dacitic rocks. Petrographic observations reveal porphyritic and glomeroporphyritic textures, oscillatory zoning, resorption rims, and sieve-textured plagioclase and amphibole, indicating magma disequilibrium and fractional crystallization. Geochemically, the rocks are calc-alkaline and display adakitic signatures, including high Sr/Y (40–80) and (La/Yb)N (25–60) ratios and low Y (<15 ppm) and Yb (<1.9 ppm) contents, consistent with high-pressure partial melting in the presence of residual garnet. Geochemical modeling indicates that the parental magma originated from low-degree (5–15%) partial melting of a high-pressure mafic source within the spinel–garnet transition zone. Negative Nb–Ti anomalies, positive Pb anomalies, and high Th/Yb ratios indicate a mantle source metasomatized by subduction-derived components. The magmas subsequently evolved through fractional crystallization with limited crustal contamination in an active continental margin during the final stages of Neo-Tethyan subduction and the onset of Arabia–Eurasia collision, providing new constraints on the origin of adakitic magmatism in southeastern Iran.