STRATIFORM CHROMITITES IN THE FARYAB OPHIOLITIC MASSIF, SOUTHERN IRAN

Mohamad Rahgoshay, Hadi Shafaii Moghadam

Abstract


The Faryab ophiolitic massif, located in the extreme southernmost Iran, contains stratiform chromites in the ultramafic portion of its cumulate sequence. The stratiform chromites alternate with thick dunitic layers. Their Cr2O3 content varies between 42 and 44% and shows lower values compared to the disseminated chromites of the dunitic layers. Pyroxenites, websterites and wherlites cumulate layers alternate with dunites. Mg# of orthopyroxenes in websterites is higher than those in pyroxenites. Chromites in pyroxenites are relatively rich in Al2O3. The forsterite content of associated olivines varies between 88.5 and 90.5. The temperatures calculated from the chromite-olivine thermometer are very low, and vary from 654 to 710°C and corresponding probably to subsolidus reactions.

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DOI: https://doi.org/10.4454/ofioliti.v30i2.243