Helium isotopic composition of hydrothermal fluids from the Manus back-arc Basin, Papua New Guinea
We present isotopic analysis of helium in hydrothermal fluids from the Manus back-arc basin, collected during the French-Japanese Manusflux and Manaute cruises in 1995 and 2000, respectively. The helium isotope composition of the fluids is comparable to that measured elsewhere in similar subduction...
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Published in | GEOCHEMICAL JOURNAL Vol. 40; no. 3; pp. 245 - 252 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
GEOCHEMICAL SOCIETY OF JAPAN
2006
The Geochemical Society of Japan |
Subjects | |
Online Access | Get full text |
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Summary: | We present isotopic analysis of helium in hydrothermal fluids from the Manus back-arc basin, collected during the French-Japanese Manusflux and Manaute cruises in 1995 and 2000, respectively. The helium isotope composition of the fluids is comparable to that measured elsewhere in similar subduction environments, with 3He/4He values (7.4 to 7.9 Ra) slightly lower than typical MORB values, except on the Manus Spreading Center (MSC) where higher values (12 ± 0.1 Ra) are observed. The causal link between the narrow spatial extent of the 3He/4He anomaly at the MSC and a 3He-rich deep mantle component remains elusive, based on available geophysical data. Thus, the Manus Spreading Center results may be an interesting example of small scale upper-mantle heterogeneity. |
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ISSN: | 0016-7002 1880-5973 |
DOI: | 10.2343/geochemj.40.245 |