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چکیده
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This study investigates the Late Eocene Davarijan granite (sensu stricto) in the northern Sanandaj-Sirjan Zone through integrated whole-rock geochemistry, Sr–Nd isotopes, and zircon U–Pb and white mica 40 Ar/39 Ar geochronology. The new data constrains the timing of crystallization, cooling, and magma sources, providing crucial insights into crustal evolution and tectonic processes in the Azna-Dorud region of the Zagros orogenic system. Zircon U–Pb ages (34.6 ± 1.9 Ma; 35.45 ± 0.42 Ma) and white–mica 40 Ar/39 Ar cooling ages (33.48 ± 0.16 Ma) indicate rapid post-emplacement cooling (∼10.5 °C/Myr) during the Late Eocene and earliest Oligocene. The granites display high-K alkaline, slightly peraluminous com- position and geochemical features typical of A–type granites (specifically of A2; by high Y/Nb). 87Sr/86Sri (0.706741–0.707001), eNd(t)(−0.99 to +0.46), and TDM2 ages (0.85–1.1 Ga), together with the presence of∼ 57 Ma inherited zircons, suggest partial melting of an isotopically rejuvenate ancient felsic crustal source (likely a tonalite) with limited mantle input. These findings strongly support a post-collisional tec- tonic setting linked to the terminal stage of the Neo-Tethys Ocean subduction and provide valuable con- straints on the geodynamic evolution of the Arabia-Eurasia collision zone.
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