Argon-helium systematics

O Iceland A Loihi Reunion Kerguelen xenoliths O Samoa xenoliths V Cameroon Line O Popping Rock Shona/SMAR N Chile Ridge 

1999) and from the Southeast Indian Ridge (Bumard et al. 2002) are consistent with such a degassing process accompanying fractional crystallization at 2-6 km depth. 

For Xe isotopes, one could extrapolate to a mantle end-member value using the e/ Ne- Xe/ Xe relationships. However, analytical uncertainties in Xe isotope analyses are sufficiently large to preclude doing this in a meaningful way at the present time. A simpler way to crudely estimate the amount of radiogenic Xe in a sample is to assume that all calculate °Ar.  

The theoretical He / Xe ratio, calculated from Equations (1) and (6), is 4.5x10 

There is much less Xe isotope data available than for the other noble gases. Nevertheless, it is remarkable that once again the Iceland basalt glasses analyzed by Trieloff et al. (2000) and the MAR popping rock show values similar to the expected production ratios for the mantle. 

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Hilton, D. R., Hammerschmidt, K., Loock, G., Friedrichsen, H. (1993) Helium and argon isotopic systematics of the central Lau Basin and Valu Fa Ridge Evidence of crustal/mantle interactions in a back-arc basin. Geochim. Cosmochim. Acta, 57, 2819—41. 

Valbracht, P. I, Honda, M., Matsumoto, T., Mattielli, N., McDougall, I., Ragettli, R., Weis, D. (1996) Helium, neon and argon isotope systematics in Kerguelen ultramafic xenoliths Implications for mantle source signatures. Earth Planet. Sci. Lett., 138, 29-38. 

Hu R, Bumard PG, Turner G, Bi X (1998) Helium and argon isotope systematics in fluid inclusions of Machangquing copper deposit in west Ymman province, China. Chem Geol 146 55-63 Hutcheon I (1999) Controls on the distribution of non-hydrocarbon gases in the Alberta Basin. Bull Can Petrol Geol 47 573-593... 

Beyond these well established characteristic features however the total width of the electron distributions is much narrower for the argon target than for neon or helium. These patterns are due to the signatures of the initial state wave function. In figure 3, a systematic discrepancy between experiment and theory appears at higher electron energies. This discrepancy occurs due to one of the basic postulates of the CDW-EIS model, namely that it is based on the independent electron model which considers there... 

Dunai, T. X, Baur, H. (1995) Helium, neon, and argon systematics of the European subcontinental mantle Implications for its geochemical evolution. Geochim. Cosmochim. Acta, 59, 2767-83. 

In this section, we review noble gas systematics of arc-related volcanism worldwide. Helium isotope studies dominate because most arc products are erupted subaerially, and air contamination is a relatively minor (correctable) problem for helium this is not the case for Ne-Ar-Kr-Xe isotope systematics. Consequently, this section is weighted towards reporting observations of helium isotope variations in arc-related minerals and fluids. However, we summarize also the available database for neon, argon and xenon isotopes (todateKr shows only air-like isotopic compositions). Finally, we consider the limited database of the relative abundances of the noble gases in arc-related products. 

Honda M, Patterson DB (1999) Systematic elemental fractionation of mantle-derived helium, neon, and argon in mid-oceanic ridge glasses. Geochim Cosmochim Acta 63 2863-2874 Honda M, McDougall I, Patterson DB, Doulgeris A, Clague DA (1991) Possible solar noble-gas component in Hawaiian basalts. Nature 349 149-151... 

Systematic changes of the shapes of the critical curves are also found for other families, where a fixed component 1 (like methane, ethane, ethene, nitrogen, tetra-fluoromethane, helium, argon, xenon, sulfur hexafluoride, methanol, ammonia, etc.) is combined with a second component 2, which is systematically varied. For reviews and references see [2-6,10-12]. A compilation of the literature concerning experimental methods and systems investigated (1978-1987) is given in [31], and of gas-liquid critical data for mixtures in [32]. 

Afterglow experiments in pure helium. Some of the first systematic studies of discharge afterglows were made by Phelps and Molnar (1953) in argon, neon, and helium. Soon afterwards improvements in the techniques for measuring small, time-dependent absorption coefficients allowed Phelps (1955) to make a more detailed study of the collision pro-... 

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