Basalts helium isotopes

Menzies MA, Kempton PD, Dungan M (1985) Interaction of continental lithosphere and asthenospheiic melts below the Geronimo Volcanic Field, Arizona, USA. J Petrol 26 663-693 Moreira M, Kurz MD (2001) Subducted oceanic lithosphere and the origin of the high p basalt helium isotopic signature. Earth Planet Sci Lett 189 49-57... 

Nishio Y, Sasaki S, Gamo T, Hiyagon H, Sano Y (1998) Carbon and helium isotope systematics of North Fiji basin basalt glasses carbon geochemical cycle in the subduction zone. Earth Planet Sci Lett 154 127-138... 

Hanan B. and Graham D. (1996) Lead and helium isotope evidence from oceanic basalts for a common deep source of mantle plumes. Science 111, 991-995. 

Figure 3 Compilation of helium isotope data from MORBs, continental hotspots, ocean island basalts, and HIMU sources (reproduced by permission of Mineralogical Society of America from Rev. Mineral. Geochem., 2002,...

Extensive volcanism can be found in eastern Africa associated with the East African rift system. Helium isotope ratios measured in basalts from the Ethiopian Rift Valley and Afar, near the triple junction of Red Sea, Aden, and Ethiopian rift systems, are 6-17/ a (Marty et al., 1993, 1996 Scarsi and Craig, 1996). These values include MORB ratios as well as indications of both contributions from radiogenic He and high He/ He hotspots. To the south, the rift system divides into eastern and western branches. Xenoliths from Tanzanian vents in the eastern branch... 

Dodson A., DePaolo D. J., and Kennedy B. M. (1998) Helium isotopes in lithospheric mantle evidence from Tertiary basalts of the western USA. Geochim. Cosmochim. Acta 62, 3775-3787. 

Scarsi P. and Craig H. (1996) Helium isotope ratios in Ethiopian rift basalts. Earth Planet. Sci. Lett. 144, 505—516. 

In southeast Australia, this conclusion has been supported by recent osmium-isotopic studies of the Quaternary Newer Volcanic Province, which reveal that sodic alkali basalts there have osmium-isotopic compositions indistinguishable from OIB, again supporting a sublithospheric origin for their parental magmas (McBride et al, 2001). Helium-isotope data are available primarily from sodic basalts in the northern half of Africa (Cameroon Line, Sudan). These basalts have R/Ri, values (—5.1-7.5) consistent with a derivation from an HIMU-type plume source (Barfod et al., 1999 Franz et al, 1999). 

Figure 1 Helium isotope data from various mantle-derived volcanics. The upper axis is the He/ He ratio R) normalized to the atmospheric ratio Rj f. As indicated by the data for selected segments of the MORB away from ocean islands falls almost entirely within the range of (7-9)Ra- While there are hotspot basalts that are characterized by high U/Pb ratios and low He/ He ratios (HIMU), many major oceanic hotspots, as well as continental hotspots, have high He/" He ratios (source Porcelli and Ballentine, 2002).

Rison W. and Craig H. (1983) Helium isotopes and mantle volatiles in Loihi Seamount and Hawaiian Island basalts and xenoUths. Earth Planet. Set Lett. 66, 407-426. 

Kamber, B. S. Collerson, K. D. 1999. Origin of ocean island basalts a new model based on lead and helium isotope systematics. Journal of Geophysical Research, 104, 25479-25491. 

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... 

Halliday AN, Davidson JP, Holden P, DeWolf C, Lee D-C, Fitton JG (1990) Trace-element fractionation in plumes and the origin of HIMU mantle beneath the Cameroon line. Nature 347 523-528 Hamano Y, Ozima M (1978) Earth-atmosphere evolution model based on Ar isotopic data. In Alexander EC, Ozima M (eds) Terrestrial Rare Gases. Center for Academic Publications Japan, Tokyo, p 155-171 Hamelin B, Dupre B, Allegre C-J (1984) Lead-strontium isotopic variations along the East Pacific Rise and the Mid-Atlantic Ridge a comparative study. Earth Planet Sci Lett 67 340-350 Hanan BB, Graham DW (1996) Lead and helium isotope evidence from oceanic basalts for a common deep source of mantle plumes. Science 272 991-995... 

Hanan BB, Graham DW, Michael PJ (1994) Highly correlated lead, strontium and helium isotopes in Mid-Atlantic Ridge basalts from a dynamically evolving spreading centre at 31-34°S. Mineral Mag 58A 370-371... 

Kingsley RH, Schilling J-G (1995) Carbon in mid-Atlantic ridge basalt glasses from 28°N to 63 °N Evidence for a carbon-enriched Azores mantle plume. Earth Planet Sci Lett 129 31-53 Kirstein LA, Timmerman MJ (2000) Evidence of the proto-Iceland plume in northwestern Ireland at 42 Ma from helium isotopes. J Geol Soc Loud 157 923-927... 

Lupton JE, Baker ET, Massoth GJ (1989) Variable He/heat ratios in submarine hydrothermal systems evidence from two plumes over the Juan de Fuca Ridge. Nature 337 161-164 Lupton JE, Graham DW, Delaney JR, Johnson HP (1993) Helium isotope variations in Juan de Fuca Ridge basalts. Geophys Res Lett 20 1851-1854... 

Marty B, Pik R, Yirgu G (1996) Helium isotopic variations in Ethiopian plume lavas nature of magmatic sources and limit on lower mantle contribution. Earth Planet Sci Lett 144 223-237 Marty B, Upton BGJ, Ellam RM (1998) Helium isotopes in early Tertiary basalts, northeast Greenland evidence for 58 Ma plume activity in the North Atlantic-Iceland volcanic province. Geology 26 407-410... 

Poreda RJ, Schilhng J-G, Craig H (1993) Helium isotope ratios in Easter Microplate basalts. Earth Planet Sci Lett 119 319-329... 

Scarsi P (2000) Fractional extraction of helinm by crashing of olivine and clinopyroxene phenociysts effects on the He/ He measured ratio. Geochim Cosmochim Acta 64 3751-3762 Scarsi P, Craig H (1996) Helium isotope ratios in Ethiopian Rift basalts. Earth Planet Sci Lett 144 505-516... 

Steinberger B, O Connell RJ (1998) Adveetion of plumes in mantle flow implieations for hotspot motion, mantle viscosity and plume distribution. Geophys J Inti 132 412-434 Stolper EM, Holloway JR (1988) Experimental determination of the solubihty of earbon dioxide in molten basalt at low pressme. Earth Planet Sei Lett 87 397-408 Stuart FM, Ellam RM, J. HP, Fitton JG, Bell BR (2000) Constraints on mantle plumes from the helium isotope composition of basalts from the British Tertiary Igneous Provinee. Earth Planet Sei Lett 177 273-285... 

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