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Contrasting geophysical and geochemical signatures of a volcano at the axis of the Wharton Fossil Ridge (N‐E Indian Ocean)
Author(s) -
Hébert Hélène,
Villemant Benoît,
Deplus Christine,
Diament Michel
Publication year - 1999
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 - 10.1029/1999gl900160
Subject(s) - geology , seafloor spreading , seamount , magmatism , lithosphere , volcano , basalt , mantle (geology) , oceanic basin , ridge , geochemistry , geophysics , seismology , structural basin , paleontology , tectonics
The Styx volcano is a prominent seamount (20–30 km diameter, 2500 m high) located at the axis of the Wharton fossil spreading center (N‐E Indian Ocean), where seafloor spreading stopped 40 Ma ago. Gravity modeling shows that it was emplaced on a weak lithosphere, in agreement with an on axis origin when seafloor spreading was active. The rocks dredged at the summit of the volcano are extreme typical alkaline basalts, indicating a deep enriched mantle source. We show here that most of this seamount was emplaced during the final stage of the seafloor spreading in the Wharton Basin. We then discuss how alkaline magmatism can be emplaced at the summit of the Styx.