Geochemical and mineralogy study of the West Rudan ophiolite Melange with emphasis on chromite ore

Document Type : Research

Authors

1 Department of Geology, Faculty of Scinces, Shahid beheshti university, Tehran

2 2- Department of Geology, Faculty of Basic Sciences, University of Sistan and Baluchistan, Zahedan, Iran

Abstract

The Rudan ophiolite complex in Hormozgan Province is located at the boundary between the Zagros structural zone in the south and the Makran-Sanandaj-Sirjan zone in the north. The ultramafic rocks, as the main constituents of this complex, consist mainly of dunite, harzburgite with minor chromitite, which are heavily serpentinized. In this study, geological methods (structural geology and alteration related to mineralization) and geochemical analyses were employed to explore minerals associated with the ophiolite exposures in western Rudan. Geochemical analyses including X-ray fluorescence (XRF), alkaline fusion (AF), induced coupled plasma spectrometry (ICP), and fire assay (FA) were conducted. Results indicate that the western Rudan ophiolites are prospective for magmatic iron, copper, and chromite mineralization. Conversely, they are poor in platinum group elements and gold enrichment. Chromite mineralization occurs in ultramafic units and within the host harzburgite rocks, appearing as disseminated grains, lens-shaped bodies, and vein-veinlet structures. Primary textures of chromite in peridotitic host rocks include granular, mesh, and disseminated types, while secondary textures of chromite-bearing rocks include shear, mylonitic, and cataclastic textures. Based on XRF analysis of chromitite samples, the Cr₂O₃ content ranges from 21.37 to 55.08 wt.%, Fe₂O₃ ranges from 7.13 to 15.88 wt.%, and Al₂O₃ ranges from 5.44 to 16.87 wt.%. The high Cr₂O₃ content in the chromitites of the studied area is consistent with high-grade alpine-type chromitites. Field and laboratory studies show that increased serpentinization correlates with increased chromite potential, especially in harzburgites. The grade of chromite in economic occurrences varies between 20% and 75%, making mining feasible given sufficient reserve.

Keywords

References

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History

  • Receive Date: 23 July 2025
  • Revise Date: 09 September 2026
  • Accept Date: 28 September 2025

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