In the east of Tafresh, an extensive set of dykes of Miocene age has intruded into Eocene volcanic and sedimentary units. Geochemically, the mafic and intermediate dykes exhibit characteristics of rocks associated with the calc-alkaline series with medium potassium content. In rare earth element (REE) patterns, the LREE elements are somewhat enriched compared to MREE (with an average (La/Sm)Cn ratio of about 2), whereas MREE do not show significant enrichment relative to HREE. In the incompatible element patterns, the enrichment of LILE and the depletion of HFSE compared to LREE resemble the patterns of magmatic rocks associated with subduction zones. However, the geochemical characteristics of the studied rocks are similar to those of igneous rocks formed in an intra-continental back-arc basin.
It appears that in the final stages of the subduction of the Neo-Tethys beneath Central Iran, a reduction in subduction rate and the subsequent increase in the dip of the subducting slab led to the dominance of extensional tectonics in the region. This extensional tectonics resulted in the thinning of the lithospheric mantle and continental crust, accompanied by the ascent of the asthenosphere. The lithospheric mantle, previously influenced by fluids and melts released from the subducting slab, underwent partial melting, generating magmas with subduction-related geochemical signatures. The development of extensional fractures in the Paleogene units provided suitable space for the emplacement of the dykes during the Miocene.
Ahmadi, A. and Hosseini, B. (2025). Geochemistry and Petrogenesis of Mafic and intermediate dyke Swarms in Eastern Tafresh (Urumieh-Dokhtar magmatic belt). Petrological Journal, (), -. doi: 10.22108/ijp.2025.143646.1347
MLA
Ahmadi, A. , and Hosseini, B. . "Geochemistry and Petrogenesis of Mafic and intermediate dyke Swarms in Eastern Tafresh (Urumieh-Dokhtar magmatic belt)", Petrological Journal, , , 2025, -. doi: 10.22108/ijp.2025.143646.1347
HARVARD
Ahmadi, A., Hosseini, B. (2025). 'Geochemistry and Petrogenesis of Mafic and intermediate dyke Swarms in Eastern Tafresh (Urumieh-Dokhtar magmatic belt)', Petrological Journal, (), pp. -. doi: 10.22108/ijp.2025.143646.1347
CHICAGO
A. Ahmadi and B. Hosseini, "Geochemistry and Petrogenesis of Mafic and intermediate dyke Swarms in Eastern Tafresh (Urumieh-Dokhtar magmatic belt)," Petrological Journal, (2025): -, doi: 10.22108/ijp.2025.143646.1347
VANCOUVER
Ahmadi, A., Hosseini, B. Geochemistry and Petrogenesis of Mafic and intermediate dyke Swarms in Eastern Tafresh (Urumieh-Dokhtar magmatic belt). Petrological Journal, 2025; (): -. doi: 10.22108/ijp.2025.143646.1347
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