[SCG56-P13] High resolution X-ray computed tomography and scanning electron microscopy studies of inclusions in Oman podiform chromitite: implications for rapid cooling in Moho Transition Zone
Keywords:Chromitite, Melt inclusion, Samail ophiolite, Oman Drilling Project
The 3D HRXCT and SEM images showed the spatial distributions of inclusions and the skeletal morphology of the host chromite. Under the rapid cooling, the host chromites grew skeletal crystals to trap melt inclusions . After trapping melt inclusions, the host chromite continued to grow on the inner wall of the inclusions . This overgrowth may be recognized as a high-Cr# chromite lining. Many previous studies of the inclusions in chromites have ignored the influence of the formation of lining . The initial Cr content of the melt inclusions should have been much higher than previously estimated, suggesting that the parental melt for the chromitite may have been highly enriched in Cr, being supersaturated in chromite. Moreover, the 3D distribution of inclusions in host chromite with skeletal morphology implies that the formation of inclusions depended on the cooling rate of chromite-forming melt, implying that the parental melt of the chromitite was rapidly cooled in the Moho Transition Zone.
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