Cadomian Magmatism in the Muteh–Golpaygan Area, Iran: Insights into Crustal Growth and Tectono-Magmatic Evolution

The Muteh–Golpaygan metamorphic complex, situated within the Sanandaj–Sirjan zone of Iran, represents a pivotal site for investigating the late Neoproterozoic Cadomian orogeny and its implications for crustal evolution along the northern margin of Gondwana. This study integrates geochemical, isotopic, and geochronological data to elucidate the petrogenesis, magma sources, and geodynamic significance of granitic (ortho-) gneisses from this region. The granitic gneisses are predominantly peraluminous and calc-alkaline, with A/CNK [molar Al₂O₃/(CaO + Na₂O + K₂O)] values ranging from 1.05 to 1.43. They exhibit enrichment in light rare earth elements (LREEs), flat heavy REE (HREE) patterns, and pronounced negative Eu anomalies, suggesting that the magma was derived from subduction-related melts that interacted with metasedimentary materials in the upper crust. Zircon U-Pb geochronology reveals crystallization ages of ~570–560 Ma, with inherited zircons dating back to the Neoarchean and Paleoproterozoic. Isotopic signatures, including εHf(t) values (−7.2 to +6.2) and δ18O values (+7.07‰ to +9.88‰), indicate a complex interplay between juvenile mantle-derived components and reworked crustal materials. Geodynamically, the magmatic characteristics align with an active continental margin setting driven by the subduction of the Proto-Tethys Ocean. Comparisons with coeval magmatism in the Arabian–Nubian Shield and Anatolia indicate a unified tectonic framework along the northern margin of Gondwana. This study provides critical insights into the tectono-magmatic processes of the Cadomian orogeny, emphasizing the roles of subduction dynamics, crustal recycling, and juvenile contributions in shaping the early continental lithosphere.