The deep structure of the Iranian Plateau

• High resolution deep structures beneath a seismic profile in Iran are defined.
• This deep structure could be the result of the coalescence of two subduction zones.
• The results confirm the presence of crustal roots at the north and south of Iran.
• The lithosphere of the Arabian Plate gently plunges NNE-ward beneath Central Iran.

High resolution structures of the lithosphere–asthenosphere system beneath a seismic profile in Iran are obtained by the simultaneous inversion of data from receiver functions and fundamental mode Rayleigh wave group velocity and validated by modeling Bouguer gravity anomaly data. The seismic data are gathered over a profile extending across Zagros, Sanandaj–Sirjan Zone (SSZ), Urumieh–Dokhtar magmatic arc (UDMA), Central Iran, Alborz–Binalud Mountain ranges and Kopeh Dagh Mountain ranges. The results confirm the presence of crustal roots at the north and south of Iranian Plateau where it meets the Arabian Plate and Eurasia. The high velocity lithosphere of the Arabian Plate gently plunges NNE-ward beneath Central Iran supporting the subduction of the continental lithosphere responsible for the seismicity of the area. The crust and lithosphere are thinner beneath Central Iran, where two low velocity structures are very likely related to magma sources of the UDMA and in east of Iran, around Lut block, where the volcanism shows calcalkaline subduction-related geochemistry. The crustal-lithospheric root to the north of the Iranian Plateau may represent the relict of a previous “cimmeric” subduction zone. Therefore the Iranian lithosphere–asthenosphere system could be the result of the coalescence of two separate subduction zones.

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