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Helium‐3 plume over the East Pacific Rise at 25°S
Author(s) -
Takahata Naoto,
Agarwal Meetu,
Nishizawa Manabu,
Shirai Kotaro,
Inoue Yumiko,
Sano Yuji
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023076
Subject(s) - plume , helium , geology , isotopes of helium , mantle (geology) , panache , seawater , pacific ocean , mantle plume , oceanography , neon , geophysics , paleontology , physics , meteorology , tectonics , atomic physics , argon , lithosphere
We have measured helium isotopic ratios of sixty‐eight water samples collected in the southeastern Pacific at 25°S. The maximum excess 3 He of 47.5% is observed just above the East Pacific Rise, which is comparable to that of 50.5% at 15°S in literature. A negative correlation between helium isotopes and neon to helium ratios of seawater samples suggests that the source of excess helium‐3 in the mid‐depth water is considered to be a MORB‐type mantle. Contour of excess 3 He shows symmetrical pattern, that is, plume of 30% excess can be traced up to 1000 km on both east and west of the East Pacific Rise. This pattern is consistent with a northward flow along the rise at 25°S estimated by a physical model. Our observation also supports a flow pattern of deep ocean currents, which has been suggested by contour of excess 3 He obtained from previous studies.