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Tracing the petrogenesis of fossil magma reservoirs using enclaves in the Damavand stratovolcano, northern Iran

par Zadsaleh, Mohsen;Pourkhorsandi, Hamed;Debaille, Vinciane ;De Jong, Jeroen ;Fontijn, Karen ;Masoudi, Fariborz
Référence Acta Geochimica
Publication Publié, 2026-04-01

Article révisé par les pairs

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Résumé :

Damavand stratovolcano is situated within the central Alborz Mountains in northern Iran. Numerous studies have delved into the geodynamics and the factors contributing to the formation of Damavand volcano in the Alborz Mountains. The volcano comprises multiple lava flows and pyroclastic deposits, predominantly consisting of trachyte and trachyandesite. The lava flows often contain enclaves with various lithological compositions like monzonite, monzodiorite and monzogabbro, and these provide valuable insights into the magmatic history and evolution of Damavand volcano. Isotopic data (143Nd/144Nd = 0.512559–0.512623; 87Sr/86Sr = 0.704745–0.704929; 176Hf/177Hf = 0.282722–0.282773) indicate changes in the magma source during volcanic activity, although isotopic compositions of both the enclaves and their host rocks have similar 143Nd/144Nd vs 87Sr/86Sr values, which lie close of the Bulk Silicate Earth values. Trace elements indicate that Damavand volcano is geochemically adakitic (mainly low-silica adakites). The εNd values vs 87Sr/86Sr isotope ratios for both the enclaves and the host rocks further support the interpretation that these rocks are primarily adakites derived from a thickened lower crust. The interpretation of the petrographic, elemental and isotopic data suggests that the enclaves at Damavand volcano did not originate from a single eruption or phase. Instead, these enclaves are fragments of ancient magma reservoirs that crystallized at depth and were later brought to the surface by subsequent eruptions. The εNd vs 87Sr/86Sr isotope ratios further indicate that, as the volcano evolved over time, magma migration occurred from deeper to shallower depths in the Earth’s crust. This trend reflects the changing dynamics of magma generation and movement within the volcanic system, shedding light on the complex evolution of Damavand volcano. By studying these processes, we can gain valuable insights into the magmatic history and behavior of the volcanic systems and their evolution.