Meteorites xenon

Krummenacher D., Merrihue C. M., Pepin R. O., and Reynolds J. H. (1962) Meteoritic krypton and barium versus the general isotopic anomalies in meteoritic xenon. Geochim. Cosmochim. Acta 26, 231 —249. 

The Zag meteorite fell in the western Sahara of Morocco in August 1998. This meteorite was unusual in that it contained small crystals of halite (table salt), which experts believe formed by the evaporation of brine (salt water). It is one of the few indications that liquid water, which is essential for the development of life, may have existed in the early solar system. The halite crystals in the meteorite had a remarkably high abundance of 128Xe, a decay product of a short-lived iodine isotope that has long been absent from the solar system. Scientists believe that the iodine existed when the halite crystals formed. The xenon formed when this iodine decayed. For this reason, the Zag meteorite is believed to be one of the oldest artifacts in the solar system. In this lab, you will use potassium-argon radiochemical dating to estimate the age of the Zag meteorite and the solar system. 

The anomalous micro-composition of the Martian atmosphere with regard to nitrogen, argon, neon, krypton and xenon has also been compared with trapped gases for the Martian meteorite collection (12 in total). The isotope ratios for... 

Bogard D. D. and Garrison D. H. (1998). Relative abundances of argon, krypton, and xenon in the Martian atmosphere as measured in Martian meteorites. Geochimica et Cosmochimica Acta, 62(10) 1829-1835. 

Xenon shows several interesting isotopic variations (see Figs. 3.33,3.34) including excess abundance of 129Xe, due to radioactive decay of 129I, in meteorites of... 

Busfield A, Gilmour JD, Whitby JA, Turner G (2004) Iodine-xenon analysis of ordinary chondrite halide implications for early solar system water. Geochim Cosmochim Acta 68 195-202 Busso M, Gallino R, Wasserburg GJ (1999) Nucleosynthesis in asymptotic giant branch stars relevance for galactic enrichment and solar system formation. Annu Rev Astronom Astrophys 37 239-309 Cameron AGW (1969) Physical conditions in the primitive solar nebula. In Meteorite Research. Millman PM (ed) Reidel, Dordrecht, p 7-12... 

Clayton DD (1989) Origin of heavy xenon in meteoritic diamonds. Astrophys J 340 613-619 Clayton DD, Dwek E, Woosley SE (1977a) Isotopic anomalies and proton irradiation in the early solar system. Astrophys J 214 300-315... 

Ott U (1993) Physical and isotopic properties of surviving interstellar carbon phases. In Protostars Planets III. Levy Hand Lunine JI (eds) University of Arizona Press, Tucson, p 883-902 Ott U (1996) Interstellar diamond xenon and timescales of supernova ejecta. Astrophys J 463 344-348 Ott U, Begemann F, Yang J, Epstein S (1988) S-process krypton of variable isotopic composition in the Murchison meteorite. Nature 332 700-702... 

Swindle TD, Podosek FA (1988) Iodine-Xenon dating. In Meteorites and the Early Solar System. Kerridge JF and Matthews MS (eds) University of Arizona Press, Tucson, p 1114-1146 Tang M, Lewis RS, Anders E (1988) Isotopic anomalies of Ne, Xe, and C in meteorites. I. Separation of carriers by density and chemical resistance. Geochim Cosmochim Acta 52 1221-1234 Tera F, Eugster O, Burnett DS, Wasserburg GJ (1970) Comparative study of Li, Na, K, Rb, Cs, Ca, Sr and Ba abundances in achondrites and in Apollo 11 lunar samples. Geochim Cosmochim Acta Suppl 1 1637-1657... 

Xenon is found in trace amounts in the atmosphere. It makes up just 0.086 ppm by volume of air. Xenon is the rarest of the noble gases. For every thousand-million atoms of air, there are only 87 atoms of xenon. Even so, it is recovered in commercial amounts by boiling off the xenon from fractional distillation of liquid air. Small amounts of xenon have been found in some minerals and meteorites, but not in amounts great enough to exploit. 

The characteristics of the presolar diamonds also change with the metamorphic grade of the host meteorite. F igure 5.15 shows the typical bimodal release of heavy noble gases (here illustrated by xenon) in Orgueil, an unheated chondrite. This pattern is compared to the xenon-release patterns of two ordinary chondrites that have experienced different degrees of mild metamorphism. The amount of low-temperature gas, labeled P3 for historical reasons, is a sensitive function of temperature. Its abundance correlates well with other indicators of... 

M (a) Elemental abundances and (b) xenon isotopic abundances for some exotic noble gas components (defined in Table 8.2) in meteorites. Modified from Wieler et al. (2006). 

The half-life of 244Pu (8.2 X 107 years) is short compared with the age of the earth (4.5 X 109 years), and hence this nuclide is now extinct. However, the time interval (a) between the element synthesis in stars and formation of the solar system may have been comparable with the half-life of 244Pu. It has been found recently in this laboratory that various meteorites contain excess amounts of heavy xenon isotopes, which appear to be the spontaneous fission decay products of 244Pu. The value of H calculated from the experimental data range between 1 to 3 X 108 years. The process of formation of the solar system from the debris of supernova is somewhat analogous to the formation of fallout particles from a nuclear explosion. 

Just as earlier we were able to observe mass-yield distributions of the fission products from the fissionable nuclide used in the Chinese nuclear device, it is possible to see part of the mass-yield curve from the fission of 244Pu, which was synthesized originally in a supernova. Figure 6 shows the mass-yield distribution of the excess fissiogenic xenon observed in the meteorite Pasamonte (15). 

Figure 6. Mass-yield distribution of the fissiogenic xenon isotopes in the meteorite Pasamonte (15)...

Clayton, D. D. 1989 Origin of heavy xenon in meteoritic diamonds. Astrophys. J. 340, 613-619. 

Lewis, R. S. Anders, E. 1989 Xenon HL in diamonds from the Allende meteorite x-composite nature. Lunar. Planet. Sci. XIX, 679-680. 

Marti, K. (1969) Solar-type xenon A new isotopic composition of xenon in the Pesyanoe meteorite. Earth Planet. Sci. Lett., 3, 243-8. 

Shukolyukov, Yu. A., Jessberger, E. K., Meshik, A. P., Dang Vu Minh, Jordan, J. L. (1994) Chemically fractionated fission-xenon in meteorites and on the Earth. Geochim. Cosmochim. Acta, 58, 3075-92. 

Swindle, T. D., Podosek, F. A. (1988) Iodine-xenon dating. In Meteorites and the Early Solar System, J. F. Kerridge M. S. Matthews, Eds., pp. 1127—46. Tucson University of Arizona Press. 

Wieler, R., Baur, H. (1994) Krypton and xenon from the solar wind and solar energetic particles in two lunar ilmenites of different antiquity. Meteoritics, 29, 570-80. 

However, light xenon isotopes from 129 to 124 were also over-abundant [61,67,68] in such meteorites and enriched [66] in the tiny host phase although they are not formed in fission. Whether there are at least two anomalous xenon components of different origin, remained controversial for years [69]. Eventually, the fission origin of the anomalous xenon was ruled out [70] because in a host phase containing the excess xenon no enrichment was detected for the adjacent barium isotopes 130 to 138, which are abundant fission products. 

Extra-terrestrial samples Excess xenon in meteorites 304 Extinct superheavy elements... 

For krypton and xenon abundances were derived from computer hts of aN (neutron capture cross-section times abundance) versus mass number. Nuclei that are shielded from the r-process, so-called s-only nuclei, were used for the ht and the abundances of Kr and Xe were calculated. From these data, and the isotopic composition of the solar wind, the krypton and xenon elemental abundances were calculated (Palme and Beer, 1993) and are listed in Table 1. The meteorite data given in Table 1 will be discussed in a later section. 

For most of the chemical elements, the relative abundances of their stable isotopes in the Sun and solar nebula are well known, so that any departures from those values that may be found in meteorites and planetary materials can then be interpreted in terms of planet-forming processes. This is best illustrated for the noble gases neon, argon, krypton, and xenon. The solar isotopic abundances are known through laboratory mass-spectrometric analysis of solar wind extracted from lunar soils (Eberhardt et al., 1970) and gas-rich meteorites. Noble gases in other meteorites and in the atmospheres of Earth and Mars show many substantial differences from the solar composition, due to a variety of nonsolar processes, e.g., excesses of " Ar and... 

Krot A. N., Brearley A. J., Ulyanov A. J., Biryukov V. V., Swindle T. D., Keil K., Mittlefehldt D. W., Scott E. R. D., and Nakamura K. (1998d) Mineralogy, petrography, bulk chemical, iodine-xenon, and oxygen isotopic compositions of dark inclusions in the reduced CV3 chondrite Efremovka. Meteorit. Planet. Sci. 34, 67-89. 

Swindle T. (1998) Implications of iodine-xenon studies for the timing and location of secondary alteration. Meteorit. Planet Sci. 33, 1147-1156. 

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