ArticlesSpecial Mineral Studies

Quantitative Optical and Electron-Probe Studies of the Opaque Phases

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Science  30 Jan 1970:
Vol. 167, Issue 3918, pp. 619-621
DOI: 10.1126/science.167.3918.619


Ilmenite, chrome-titanium spinel, ulvöspinel, troilite, native iron, iron-nickel alloy, and native copper are present. In addition mackinawite is provisionally identified. Three additional opaque phases are present but not identified. Modal analysis indicates that the breccia is enriched in iron relative to ilmenite and troilite, and the high nickel content of this iron suggests that it is largely of meteoritic origin. The bulk composition of liquids corresponding to iron/troilite droplets in the rocks indicates an oxygen fugacity no greater than 10-15.5 and a sulfur fugacity of 10-6 bar. Complete melting of rocks produced a glass containing complex iron/troilite globules and skeletal ilmenites.

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