Lunar materials

Among the rarest of all meteorites are the lunar meteorites. Isotopic, mineralogical, and compositional properties of these samples provide positive identification as lunar samples because of the unique properties of lunar materials that have been discovered by extensive analyses of lunar materials returned by the manned ApoUo and unstaffed Luna missions. AH but one of the lunar meteorites that have been found to date have been recovered from Antarctica. 

Occurrence and Recovery. Rhenium is one of the least abundant of the naturally occurring elements. Various estimates of its abundance in Earth s cmst have been made. The most widely quoted figure is 0.027 atoms pet 10 atoms of silicon (0.05 ppm by wt) (3). However, this number, based on analyses for the most common rocks, ie, granites and basalts, has a high uncertainty. The abundance of rhenium in stony meteorites has been found to be approximately the same value. An average abundance in siderites is 0.5 ppm. In lunar materials, Re, when compared to Re, appears to be enriched by 1.4% to as much as 29%, relative to the terrestrial abundance. This may result from a nuclear reaction sequence beginning with neutron capture by tungsten-186, followed by p-decay of of a half-hfe of 24 h (4) (see Extraterrestrial materials). 

Barretto, P.M.C., Emanation Characteristics of Terrestrial and Lunar Materials and the Radon-222 Loss Effect on the Uranium-Lead System Discordance, Ph.D. thesis, Rice University, Houston (1973). ... 

Stable isotope analysis of Earth, Moon, and meteorite samples provides important information concerning the origin of the solar system. 8lsO values of terrestrial and lunar materials support the old idea that earth and moon are closely related. On the other hand three isotope plots for oxygen fractionation in certain meteoric inclusions are anomalous. They show unexpected isotope fractionations which are approximately mass independent. This observation, difficult to understand and initially thought to have important cosmological implications, has been resolved in a series of careful experimental and theoretical studies of isotope fractionation in unimolecular kinetic processes. This important geochemical problem is treated in some detail in Chapter 14. 

Beard BL, Johnson CM (1999) High precision iron isotope measurements of terrestrial and lunar materials. Geochim Cosmochim Acta 63 1653-1660... 

In Stable Isotope Geochemistry. Rev Miner Geochem 43 415 67 Beard BL, Johnson CM (1999) High-precision iron isotope measurements of terrestrial and lunar materials, Geochim Cosmochim Acta 63 1653-1660 Beard BL, Johnson C (2004) Fe isotope variations in the modem and ancient Earth and other planetary bodies. Rev Miner Geochem 55 319-357 Beard BL, Johnson CM, Cox L, Sun H, Nealson KH, Aguilar C (1999) Iron isotope biosphere. Science 285 1889-1892... 

The chemistry of lunar materials will be considered in much greater detail in Chapter 13. 

A number of extinct radionuclides (7B, 10Be, 14C, 22Na, 26A1, 36C1, 35S, 37Ar, 41Ca) have been identified in meteorites or lunar materials.1 These radionuclides can be also used in isotope... 

Loeffler, B. M., Bums, R. G. Tossell, J. A. (1975) Metal-metal charge transfer transitions interpretation of visible-region spectra of the moon and lunar materials, Proc. 6th Lunar Sci. Confi, Geochim. Cosmochim. Acta, Suppl. 6. (Pergamon Press, New York), pp. 2663-76. 

Mass spectroscopy Spark-source mass spectroscopy has been applied to certain terrestrial and lunar materials with excellent results because of its very low detection limit and the exactness of the results. Drawbacks are the cost of the instruments and the time needed for each analysis. 

Loeffler, B. M., R. G. Burns, J. A. Tossell, D. J. Vaughan, and K. H. Johnson (1974). Charge transfer in lunar materials interpretation of ultraviolet-visible spectral properties of the Moon. Proc. 5th Lunar Sci. Conf. 3, 3007-16. 

The siderophile elements in polymict lunar materials come almost entirely from meteoritic contamination added to the outer Moon in impacts. Siderophile elements thus may give clues to the nature of the materials that have bombarded the Moon. Unfortunately, however, the limited expanse of the Apollo/Luna sampling region, with samples dominated by just three or four major basins, again severely restricts the general applicability of this approach. 

CHEMICAL COMPOSITION OF CERTAIN LUNAR MATERIALS (PERCENT BY WEIGHT) >... 

The FeO content of Mars given here is consistent with the geochemical models of Dreibus and WSnke 13) and with laboratory studies of Mars-derived SNC meteorites. Since FeO content is a sensitive marker of the temperature of origin, the original location of bulk lunar material appears to have been between the orbits of Earth and Mars. The FeO content of Mercury s crust is probably best quoted as 1.5 1.5%, since it remains without any firm detection, and its presence cannot be verified at the 3% level 14). 

The Moon is greatly depleted in volatile elements including C and H. Isotopic analyses of H in lunar materials typically reflect the isotopic composition of the solar wind (essentially D/H = 0) modified to varying degrees by terrestrial contamination (e g. Epstein and Taylor 1971). Very rare indigenous C components have <= -19 to -26 %o, and are also easily compromised by terrestrial contamination (e.g. DesMarais 1978). 

The TL curves of samples of lunar material appear at 350 C for lunar fines and 400°C for crystalline rocks (134). The TL is probably the result of an equilibrium between gains from radiation by cosmic rays bombarding the moon s surface combined with the possible presence of radioactivity in the... 

Pepin RO, Nyquist LE, Phiimey D, Black DC (1970b) Rare gases in Apollo 11 lunar material. Proc Apollo 11 Lunar Sci Conf 1435-1454... 

It is hardly necessary to comment on the epic flight of three American astronauts in Apollo 11 which resulted in their return to earth on the 24th July, 1969, with the first 22 kilograms of lunar material. These samples were distributed to scientists in nine countries for one of the most intensive investigations ever prepared, and all the preliminary results were published simultaneously in a special issue of Science in January 1970. 

Apparently, our solar system was showered by debris from a recent but distant supernova explosion which may have disturbed the "peaceful" gas cloud in our part of the universe and initiated the condensation of the solar system. At this time newly formed elements stopped being added to the solar system from the galaxy. Sufficient amounts of and Pu remained after the formation of solid materials to produce characteristic isotope anomalies and fission track excesses in meteoritic and lunar materials. The spontaneous fission decay of Pu yields which decays as... 

A futuristic application for fibre-reinforced glass matrix composites is related to the use of lunar materials for future space constmction activities. Glass/glass composites in which both the fibre and the matrix are made of fused lunar soil have been proposed [28]. These materials, obtained so far on a laboratory scale, show great promise for providing large quantities of basic structural materials for cost-effective outer-space constmction. 

The thermal preparation of polypeptides from amino acids of the type so far identified in meteor and lunar material has suggested that proteinlike polymers could exist extraterrestrially. A series of physiochemical measurements of polypeptides, particularly by CD and ORD for conformational reasons, have been undertaken with copper(II) complexes of poly-His, poly-(N -Bzl-Lys), random copolymers of Glu-Asp benzyl ester with n-Glu-Asp benzyl ester, poly-/8-(7-Glu)-Asp, and poly-(ci5-5-Me-Pro). ... 

Haskin, L.A., 1989, Rare Earth Elements in Lunar Materials, in Geochemistry and Mineralogy of Rare Earth Elements, eds B.R. Lipin and G.A. McKay (The Mineralogical Society of America, Washington, DC) Vol. 21, pp. 227-258. 

The half-life of Nd is 1.06 X 10 a with a corresponding decay constant of 6.54 X 10 aT, and the decay scheme is applicable to dating terrestrial rocks, stony meteorites, and lunar materials. 

Analytical Instrumentation. Before the Apollo Moon landings, meteorites were the only extraterrestrial materials available for astrogeologists to study. Usually the classification of a meteorite requires a certain amount of destructive analysis. In many cases, the most interesting and rare meteorites are available only in very small quantities, thereby hmiting tbe amount of material available for analysis. Similarly, only small amounts of the rocks recovered from the Moon were available for analysis. The National Aeronautics and Space Administration (NASA) deliberately preserved a large quantity of lunar material for future scientists to study with instruments not yet invented. They realized that another trip to the Moon might not occur for many years. 

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