ArticlesTrace Elements

Electron-Microprobe Analyses of Phases in Lunar Samples

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Science  30 Jan 1970:
Vol. 167, Issue 3918, pp. 517-520
DOI: 10.1126/science.167.3918.517


In fine (type A) and coarse-grained (type B) Apollo 11 lunar volcanic rocks clinopyroxenes are extremely inhomogeneous. Ferrosilite-rich areas in type B rocks have decomposed to submicron vermicular intergrowths of clinopyroxene-fayalite-cristobalite(?). Plagioclase has normal zoning with K2O up to 0.5 percent in rims. Ilmenites are relatively homogeneous with low mgo(0.1 to 2 percent) and high zro2 (up to 0.26 percent). Metal phase in troilite has <0.02 percent nickel. The breccias (type C) and fines (type D) containing 0.09 to 10.52 percent Ti02. Rare metal fragments with meteorite-like compositions occur in breccias and fines. Gross similarities between euctites and Apollo 11 volcanic rocks indiacate similar evolutionary environments, but detailed mineralogical differences suggest either separate origins or if eucrites are lunar, chemical inhomogeneities on the lunar surface.

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