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Bulk Mineralogy and Geochemistry of Selected Alaskan Chromian Spinel Samples.
MISSING :13 pages
As part of the Bureau of Mines critical and strategic minerals program in Alaska, 34 high-purity chromium spinel samples were analyzed for trace and major element geochemistry and mineralogy. The samples were analyzed by x-ray diffraction, x-ray fluorescence, and chemical techniques. Systematic differences in chemistry are evident when samples collected from the Chugach Mountains and their related extension are compared with chromian spinel samples collected from interior Alaska. Compared with the Chugach samples, the interior Alaska samples have higher average amounts of Al2O3, Fe2O3, TiO2, and NiO, have lower average amounts of FeO and Cr2O3, and exhibit greater dispersion in values. Considerable mineralogical variability of chromian spinel exists between and within individual Alaskan chromite-bearing Ultramafic complexes. Of 34 samples analyzed, 25 samples are magnesiochromite, 5 are chromite, 3 are spinel, and 1 is hercynite. As a group, the interior Alaska samples have a smaller average unit cell dimension than the Chugach group of samples. The chemical and mineralogical differences between the two groups of samples can be attributed to different genetic histories and may have implications for locating chromian spinel deposits amenable to standard beneficiating techniques.
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Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division