Mineralogy, Geochemistry, and Tectonic Setting of the Gabbroic Rocks in the Dashtak Salt Dome, Chaharmahal and Bakhtiari Province, Iran

Articles in Press

Document Type : Research

Authors

Shahrekord University

10.22128/ijcm.2025.2997.0

Abstract

The Dashtak salt dome is located in Ardal County, Chaharmahal and Bakhtiari Province, southwestern Iran. The magmatic rocks associated with this salt dome are genetically linked to the Hormuz Series and occur as scattered outcrops, comprising both intrusive rocks (microgabbros) and extrusive rocks (basalts and andesites). Petrographic investigations reveal diverse textural features, including granular, intergranular, amygdaloidal, porphyritic, and glomeroporphyritic textures. Primary minerals identified in thin sections consist of clinopyroxene, plagioclase, and olivine pseudomorphed by chlorite, while biotite and greenish-blue amphiboles are considered late-stage minerals. Secondary phases include chlorite, apatite, epidote, and iron–titanium oxides. The studied rocks exhibit SiO₂ contents ranging from 54.54 to 56.77 wt. %, MgO ranging from 5.56 to 13.52 wt. %, and total iron (FeOt) contents between 7.80 and 13.46 wt.%, collectively classifying them as mafic igneous rocks. Furthermore, the relatively wide variation in magnesium number (Mg# = 45.63–72.45) suggests notable magmatic differentiation. The widespread occurrence of titanium-rich minerals (sphene/titanite), enrichment of large-ion lithophile elements (LILEs) relative to high field strength elements (HFSEs) in chondrite-normalized multi-element diagrams, along with geochemical discriminant plots, all support an alkaline affinity for these samples. Moreover, geochemical diagrams indicate that the rocks formed in an intraplate continental setting, derived from an enriched mantle source near the garnet–spinel transition zone with minor crustal contamination.

 

Keywords

Iranian Journal of Crystallography and Mineralogy

Articles in Press, Accepted Manuscript
Available Online from 09 August 2025

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History

  • Receive Date: 03 July 2025
  • Revise Date: 09 August 2025
  • Accept Date: 29 July 2025

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