Noble Gases in the Earth's Mantle

Farley, K. A.; Neroda, E.

doi:10.1146/annurev.earth.26.1.189

Cited by 208 publications

(108 citation statements)

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“…We measured high 3 He/ 4 He ratios for high temperature fumaroles (>800°C), slightly above 8 Ra which coincides with the widely accepted MORB value of 8 ± 1 Ra (Hilton et al, 1993a;Ozima, 1994;Farley and Neroda, 1998 and references included). Compared to other Japanese volcanic systems, they correspond to the upper range of the values measured for this subduction-related volcanic zone (Nagao et al, 1981;Sano and Wakita, 1985;Marty et al, 1989).…”

Section: Resultssupporting

confidence: 86%

“…In this aim, helium has interesting properties: a gaseous state, inertness, and above all, its isotopes show contrasting ratios in the continental crust (<0.1 Ra, Ra being the atmospheric ratio) and in the upper (about 8 Ra) and lower (>30 Ra) mantle (Ozima, 1994;Farley and Neroda, 1998). Therefore it has proven to be a powerful tracer of the origin and possible crustal dilution of mantle-derived fluids (i.e., Hilton et al, 1993b;Van Soest et al, 1998) and of short-term variations induced by active volcanism (i.e., Sano et al, 1997).…”

Section: *Corresponding Authormentioning

confidence: 99%

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Helium isotopes at Satsuma-Iwojima volcano, Japan.

2002

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We present isotopic analyses of helium in fluids collected during two field trips at Satsuma-Iwojima and Shin-Iwojima islands in November 1998 and October 2000. These are the first reported helium measurements at Shin-Iwojima. Copper tubes tightly closed by clamps at both ends were used to sample 1) gases from high and low temperature fumaroles in the summit area of Iwodake cone, 2) gases from a fumarole on Shin-Iwojima, 3) gas bubbling from the sea-floor along Shin-Iwojima where an increasing bubbling intensity was observed between 1998 and 2000, 4) waters from Sakamoto and Higashi hot springs. For gas samples, two types of correction for atmospheric contamination are discussed, using either the neon concentration or just the partial pressure of condensable gases at liquid nitrogen temperature; this latter method turned out to be very efficient for many samples. For all gas samples, we found 3 He/ 4 He isotopic ratios between 7.1 and 8.2 times the atmospheric ratio, pointing to a magmatic origin for fumaroles both at Iwodake crater and at Shin-Iwojima island. Our measurements show a decrease of the isotopic ratios at Iwodake with decreasing temperature of the fumarole. Comparing the results of both field trips and those published in previous studies, we suggest this volcanic system is undergoing a recent increase of activity.served both on and off-shore, including high (>800°C) and low temperature fumaroles, hot springs and gas bubbling, which provide a good opportunity to sample and study this volcanic system. In this aim, helium has interesting properties: a gaseous state, inertness, and above all, its isotopes show contrasting ratios in the continental crust (<0

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Section: Resultssupporting

confidence: 86%

Section: *Corresponding Authormentioning

confidence: 99%

Helium isotopes at Satsuma-Iwojima volcano, Japan.

2002

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“…Measurements of Ar and Kr isotopes in ice cores can lead to estimation of firn thickness and temperature (Craig and Wiens, 1996;Severinghaus et al, 2001Severinghaus et al, , 2003. Noble gases in mantle-derived rocks have been used to infer properties of the early history of the earth (Honda et al, 1991;Hiyagon et al, 1992;Farley and Neroda, 1998). Noble gas isotopes produced by cosmic rays yield surface exposure ages for terrestrial rocks (Lal, 1991;Bierman, 1994;Schafer et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

A determination of air-sea gas exchange and upper ocean biological production from five noble gases and tritiugenic helium-3

Stanley¹

2007

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The five noble gases (helium, neon, argon, krypton, and xenon) are biologically and chemically inert, making them ideal oceanographic tracers. Additionally, the noble gases have a wide range of solubilities and molecular diffusivities, and thus respond differently to physical forcing. Tritium, an isotope of hydrogen, is useful in tandem with its daughter helium-3 as a tracer for water mass ages. In this thesis, a fourteen month time-series of the five noble gases, helium-3 and tritium was measured at the Bermuda Atlantic Time-series Study (BATS) site. The time-series of five noble gases was used to develop a parameterization of air-sea gas exchange for oligotrophic waters and wind speeds between 0 and 13 m s −1 that explicitly includes bubble processes and that constrains diffusive gas exchange to ± 6% and complete and partial air injection processes to ± 15%. Additionally, the parameterization is based on weeks to seasonal time scales, matching the time scales of many relevant biogeochemical cycles. The time-series of helium isotopes, tritium, argon, and oxygen was used to constrain upper ocean biological production. Specifically, the helium flux gauge technique was used to estimate new production, apparent oxygen utilization rates were used to quantify export production, and euphotic zone seasonal cycles of oxygen and argon were used to determine net community production. The concurrent use of these three methods allows examination of the relationship between the types of production and begins to address a number of apparent inconsistencies in the elemental budgets of carbon, oxygen, and nitrogen.

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“…Such analyses have shown that Mid Oceanic Ridge Basalts (MORB) have uniform 3 He/ 4 He ratios that are higher than the air value (Ra) by about a factor of 8. In contrast, Oceanic Island Basalts (OIB) have variable and much higher value than the air value by a factor of about 12-30 (e.g., Farley and Neroda, 1998). Volcanic gases of mantle origin have ratios similar to those in MORB.…”

Section: Introductionmentioning

confidence: 99%