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Electromagnetic evidence for volatile‐rich upwelling beneath the society hotspot, French Polynesia
Author(s) -
Tada Noriko,
Tarits Pascal,
Baba Kiyoshi,
Utada Hisashi,
Kasaya Takafumi,
Suetsugu Daisuke
Publication year - 2016
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 - 10.1002/2016gl071331
Subject(s) - hotspot (geology) , geology , upwelling , magnetotellurics , seafloor spreading , mantle (geology) , geophysics , silicate , electrical resistivity and conductivity , mineralogy , oceanography , physics , quantum mechanics , astronomy
We have conducted a seafloor magnetotelluric survey that images, for the first time, three‐dimensional electrical conductivity structure in the upper mantle beneath the Society hotspot. A striking feature in our model is a high‐conductivity anomaly a few hundred kilometers in diameter, which is continuous from the lowest part of the upper mantle to a depth of approximately 50 km below sea level. Using theoretical and experimental results from mineral physics, we interpret the high‐conductivity anomaly as evidence of the melt fraction up to 2.2 vol.%, which is robust regardless of assumed temperature, and the existence of carbonated silicate melt beneath the hotspot. Our results suggest that the Society hotspot is a pathway for ascending volatiles from the deeper part of the upper mantle to the surface.