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X-ray digital imaging petrography of lunar mare soils: modal analyses of minerals and glassesIt is essential that accurate modal (i.e., volume) percentages of the various mineral and glass phases in lunar soils be used for addressing and resolving the effects of space weathering upon reflectance spectra, as well as for their calibration such data are also required for evaluating the resource potential of lunar minerals for use at a lunar base. However, these data are largely lacking. Particle-counting information for lunar soils, originally obtained to study formational processes, does not provide these necessary data, including the percentages of minerals locked in multi-phase lithic fragments and fused-soil particles, such as agglutinates. We have developed a technique for modal analyses, sensu stricto, of lunar soils, using digital imaging of X-ray maps obtained with an energy-dispersive spectrometer mounted on an electron microprobe. A suite of nine soils (90 to 150 micrometers size fraction) from the Apollo 11, 12, 15, and 17 mare sites was used for this study. This is the first collection of such modal data on soils from all Apollo mare sites. The abundances of free-mineral fragments in the mare soils are greater for immature and submature soils than for mature soils, largely because of the formation of agglutinitic glass as maturity progresses. In considerations of resource utilization at a lunar base, the best lunar soils to use for mineral beneficiation (i.e., most free-mineral fragments) have maturities near the immature/submature boundary (Is/FeO approximately or = 30), not the mature soils with their complications due to extensive agglutination. The particle data obtained from the nine mare soils confirm the generalizations for lunar soils predicted by L.A. Taylor and D.S. McKay (1992, Lunar Planet Sci. Conf. 23rd, pp. 1411-1412 [Abstract]).
Document ID
20040089732
Acquisition Source
Johnson Space Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Taylor, L. A.
(Planetary Geosciences Institute, The University of Tennessee Knoxville 37996, United States)
Patchen, A.
Taylor, D. H.
Chambers, J. G.
McKay, D. S.
Date Acquired
August 21, 2013
Publication Date
December 1, 1996
Publication Information
Publication: Icarus
Volume: 124
Issue: 2
ISSN: 0019-1035
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: NGT5-1052
CONTRACT_GRANT: NAG9-409
Distribution Limits
Public
Copyright
Other
Keywords
NASA Discipline Exobiology
NASA Center JSC

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