Helium mantle sources

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. 

Hilton D. R., Maepherson C. G., and Elliott T. R. (2000a) Helium isotope ratios in mahe phenocrysts and geothermal fluids from La Palma, the Canary Islands (Spain) implications for HIMU mantle sources. Geochim. Cosmochim. Acta 64, 2119-2132. 

Helium isotope measurements in ocean ridge and island basalts provide some of the most basic geochemical information on mantle source reservoirs. More helium isotope analyses have been performed for oceanic volcanic rocks than for other noble gas species, and helium isotopes have played a leading role in the study of mantle heterogeneity. Helium isotope analyses are readily performed by modern mass spectrometers because there is a general absence of atmospheric contamination in samples due to the low concentration of helium in air (5.24 parts per million by volume at standard temperature and pressure). There are 2 naturally occurring isotopes of helium. He is much less abundant than " He for example, the atmospheric He/" He ratio (Ra) is 1.39x10 (Mamyrin et al. 1970 Clarke et al. 1976). Nearly all of the terrestrial " He has been produced as a-particles from the radioactive decay of U, U and Th over... 

A comparison of observed and calculated helium and heat fluxes at ocean ridges suggests that a deep mantle reservoir supplies most of the He and heat to the upper mantle (O Nions and Oxburgh 1983 Kellogg and Wasserburg 1990). The involvement of such a deep reservoir in the upper mantle heat and mass balance appears to make it inescapable that some form of stratification is present within the mantle, and that the mantle source of some ocean islands, such as Hawaii and Iceland, lies below the mantle source for ocean ridges. 

Furman T, Graham DW (1999) Erosion of lithospheric mantle beneath the East African Rift system geochemical evidence from the Kivu volcanic province. Lithos 48 237-262 Gasparon M, Hilton DR (1994) Crustal contamination processes traced by helium isotopes examples from the Sunda Arc, Indonesia. Earth Planet Sci Lett 126 15-22 Goes S, Spakman W., Bijwaard H (1999) A lower mantle source for central European volcanism. Science 286 1928-1931... 

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