Petrogenetic Study of Rhyolites from the Dehbid Area (Sanandaj–Sirjan Zone) Evidence for Crustal Melting and Post-Orogenic Evolution

Articles in Press

Document Type : Original Article

Authors

1 Faculty member of Hormozgan University

2 University lecturer

3 Faculty member, University of Hormozgan

10.22128/ijcm.2025.3044.1008

Abstract

The Dahbid rhyolites in the southern Sanandaj–Sirjan Zone occur as small intrusive bodies with a subalkaline composition, high silica, low TiO2, Fe2O3t, and MgO, high differentiation index, and normative corundum >1%, reflecting a peraluminous S-type granite affinity. The presence of biotite, muscovite, sphene, apatite, and zircon together with low Nb/Ta and Zr/Hf ratios confirms a crustal magma source. Variations of Th and Th/U indicate an intermediate position between S- and I-type granites and partial melting of the middle to lower continental crust. REE patterns show LREE enrichment, lack of strong HREE depletion, and pronounced negative Eu anomalies, suggesting residual plagioclase in the source. Zircon saturation index indicates low melting temperatures (<800 °C) and pressures (<300 MPa) for sedimentary protoliths. These features resemble low-temperature peraluminous granites in high-pressure post-collisional orogens and represent crustal melting in a thickened continental setting.

Keywords

Iranian Journal of Crystallography and Mineralogy

Articles in Press, Accepted Manuscript
Available Online from 23 September 2025

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History

  • Receive Date: 02 September 2025
  • Revise Date: 22 September 2025
  • Accept Date: 23 September 2025

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