CORRECTION, CORRELATION, AND THEORETICAL CONSIDERATION OF LUNAR X-RAY FLUORESCENCE INTENSITY RATIOS.

摘要

Lunar orbital X-ray fluorescence (XRF) data obtained during the Apollo 15 and 16 missions are corrected, correlated with related lunar data sets, and compared to theoretically calculated X-ray fluorescence and scatter data.;Orbital variations in the background, which, it was thought, might have been a source of interorbital variation in the Mg/Si data, are investigated, and no such systematic variations in the background are found. In fact, the large degree of intraregional variation relative to interregional variation of XRF/Si intensities is found to be consistent with a similar trend of magnesium variation among lunar rock types.;A semi-quantitative color correlation technique is developed to compare related remote sensing data. This method is successfully used to correlate Al/Si ratios to elevation data (laser altimetry), visbile albedos, and Fe values (Gamma-ray data in the 2.75-8.60 MeV range). The correlations and their relationship to Mg/Si data are discussed.;Theoretical calculations of the expected X-ray flux for Si, Al, and Mg at typical lunar soil concentrations compared favorably with orbital measurements for these soils. Scattering data calculated for Si, Al, and Mg for typical lunar soils, are found to be largely independent of concentration. The minimum concentration at which Mg and Al can be detected from orbital data is determined.;XRF Mg/Si and Al/Si ratios are corrected for variations in solar activity, a principal source of spurious interorbital variation, by the use of the Tucker-Koren solar model and independent solar flux measurements from the Solrad 10 satellite. Improvement in definition of known geological features is seen on orbital images of XRF intensity ratios after the data has been corrected in this manner. A statistical technique used to show the degree of elimination of spurious interorbital variation includes linear regression analysis.