Lunar rock

Zirconium is found in abundance in S-type stars, and has been identified in the sun and meteorites. Analysis of lunar rock samples obtained during the various Apollo missions to the moon show a surprisingly high zirconium oxide content, compared with terrestrial rocks. 

Element Igneous rocks Clays and shales Meteorites Lunar rocks Oceans... 

Tera F, Wasserburg GJ (1972) U-Th-Pb systematics in three Apollo 14 basalts and the problem of initial Pb in lunar rocks. Earth Planet Sci Lett 14 281-304... 

The phosphorus chemistry occurring in interstellar matter and in the circum-stellar regions of the cosmos is not yet understood. We do, however, know that phosphorus compounds are present in meteorites, lunar rocks and Mars meteorites. Oddly enough, the element can be detected nearly everywhere, though only in low concentrations. Phosphate minerals, as well as the anions PO2 and PO3, have... 

Among the oldest rocks on Earth are those on Isua, an island off the coast of Greenland they are 3.8 Gyr old, formed some 0.7 Gyr after accretion of the Earth. The rocks mark the beginning of the Archean period of geological time. The Isua rocks suggest that there was an extensive hydrosphere at this time, with erosion, transportation and deposition of minerals from water solution. The oldest lunar rocks, however, record an earlier high-temperature event - the Earth-Moon capture event. 

A study of the surface helium, neon, and argon in lunar rocks illustrates the sensitivity of the laser microprobe [3]. Lunar rock 12054 was collected from the surface of the moon with known orientation. This rock contains a glass coating which covers the face including a crack. As a result, part of the surface in the crack is never exposed directly to the sun whereas other parts are directly exposed. We made a traverse across the surface analyzing the gas from individual laser pits. Four types of sites were analyzed in this study. 

Immature soil samples have S Te values that are indistinguishable from lunar rocks, whereas submature and mature soils have 5 Fe values that are greater than those of lunar rocks, and S Te values are positively correlated with Ig/FeO values (Fig. 12). Lunar regolith samples in general tend to have heavy isotopic compositions as compared to lunar rock samples, as demonstrated by isotopic analyses of O, Si, S, Mg, K, Ca, and Cd (Epstein and Taylor 1971 Clayton et al. 1974 Russell et al. 1977 Esat and Taylor 1992 Humayun and Clayton 1995 Sands et al. 2001 Thode 1976). The origin of isotopic compositions that are enriched in the heavy isotopes has been presumed to reflect sputtering by solar wind and vaporization, where preferential loss of the lighter isotope to space occurs. In contrast to previous isotopic studies, the Fe isotope compositions measured in the Lunar Soil Characterization Consortium samples can be related to a specific phase based on the positive correlation in Ig/FeO and 5 Fe values (Fig. 12). 

Onuma et al. 1970). By comparison with other terrestrial rocks, the range of observed 8 0-valnes is very narrow. For instance, terrestrial plagioclase exhibits an O-isotope variation which is at least ten times greater than that for all lunar rocks (Taylor 1968). This difference may be attributed to the much greater role of low-temperature processes in the evolution of the Earth s crust and to the presence of water on the Earth. 

The most notable feature of the sulfur isotope geochemistry of lunar rocks is the uniformity of 8 " S-values and their proximity to the Canyon Diablo standard. The range of published 8 " S-values is between -2 to +2.5%o. However, as noted by Des Marais (1983), the actual range is likely to be considerably narrower than 4.5%o due to systematic discrepancies either between laboratories or between analytical procedures. The very small variation in sulfur isotope composition supports the idea that the very low oxygen fugacities on the Moon prevent the formation of SO2 or sulfates, thus eliminate exchange reactions between oxidized and reduced sulfur species. 

Example 5.7. The oldest lunar rock known to date is a lunar highland anorthosite 60025. The data for different minerals in a single rock are shown in the table below (Carlson and Lugmair, 1988). Find the age. 

Tera, F. and Wasserburg, G.J., 1972. U-Th-Pb systematics in three Apollo 14 basalts and the problem of initial Pb in lunar rocks. Earth Planet. Sci. Lett., 14 281-304. Titterington, D.M. and Halliday, A.N., 1979. On the fitting of parallel isochrons and the method of maximum likelihood. Chem. Geol., 26 183-195. 

Tera, F. and Wasserburg, G. J. (1974) U-Th-Pb systematics on lunar rocks and inferences about lunar evolution and the age of the Moon. Proceedings of the 5th Lunar Science Conference, Geochimica et Cosmochimica Acta Supplement, 5, 1571-1599. 

Published geochemical studies of lunar rocks are voluminous. Compilations of lunar rock analyses can be found in The Lunar Sourcebook (Taylor et al., 1991) and Planetary Materials (Papike et al., 1998). 

Lunar rocks Ferroan anorthosite Lunar meteorite... 

Analyses of thorium and FeO in lunar rocks and lunar meteorites can be described by three compositional end members - ferroan anorthosite, KREEP, and mare basalt. The various lunar terranes defined by orbital measurements of Th and FeO, illustrated by shaded and hatched fields, can also be explained by mixtures of these components. Terrane abbreviations are PKT (Procellarum KREEP Terrane) FHT (Feldspathic Highlands Terrane) SPA (South Pole-Aiken Terrane). Modified from Jolliff etal. (2000). 

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