The distinction of rock types on the basis of their mass spectra, with special reference to lunar-surface applications

Abstract

It is shown that the rock types most commonly expected to be encountered on the lunar surface can for the most part be readily distinguished, chemically, by plotting their relative concentrations of Fe, Mg, and Al on a ternary variation diagram. The necessary data for characterizing as unknown as to rock type can be quite easily extracted from complete or partial mass spectra such as may be obtained by means of a robot mass spectrometer on the lunar surface. For most compositions, determination of only two nuclide or element rations will characterize the sample. Fo others, the determination of one additional ratio or comparison with a few standard spectra previously obtained in the laboratory may be necessary to clarify the unknown in terms of the chemistry of the terrestrial or meteoritic equivalents. No quantitative assay of element concentrations is necessary for such a first classification.