Upwelling, rifting, and age-progressive magmatism from the Oki Daito mantle plume

Volcanism at the western margin of the Pacific Ocean has developed above subducting ocean crust, generating island arcs and spreading basins; however, the controls on magmatism at and before the initiation of subduction are less clear. We present new 40Ar/39Ar data from a 1000 km northwest-southeast...

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Bibliographic Details
Published in:Geology (Boulder) 2013-09, Vol.41 (9), p.1011-1014
Main Authors: Ishizuka, Osamu, Taylor, Rex N, Ohara, Yasuhiko, Yuasa, Makoto
Format: Article
Language:English
Subjects:
absolute age
Ar/Ar
basalts
Basins
Cenozoic
crust
dacites
Deep Sea Drilling Project
DSDP Site 292
DSDP Site 294
DSDP Site 446
DSDP Site 447
Geology
Geophysics
igneous and metamorphic rocks
igneous rocks
IPOD
isotope ratios
isotopes
Japan Sea
lead
Leg 195
Leg 31
Leg 59
Magma
mantle plumes
Marine
metals
North Pacific
Northwest Pacific
northwestern Philippine Sea
Ocean Drilling Program
ocean floors
oceanic crust
ODP Site 1201
Oki Ridge
Pacific Ocean
Pb-206/Pb-204
Pb-208/Pb-204
Petrology
Philippine Sea
Philippine Sea Plate
plate tectonics
plateaus
radioactive isotopes
sea-floor spreading
seamounts
solid Earth (tectonophysics)
stable isotopes
volcanic rocks
volcanism
Volcanoes
West Pacific
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Summary:Volcanism at the western margin of the Pacific Ocean has developed above subducting ocean crust, generating island arcs and spreading basins; however, the controls on magmatism at and before the initiation of subduction are less clear. We present new 40Ar/39Ar data from a 1000 km northwest-southeast line of oceanic plateaus on the Philippine Sea plate demonstrating that they formed as a time-progressive volcanic chain mirrored on either side of the West Philippine Basin backarc spreading center. In the north this chain is bounded by a Mesozoic remnant arc, and in the south by subduction beneath the Philippine arc. Geochemically these oceanic plateaus have an EM-2 (enriched mantle 2) ocean island basalt signature matching the older 45-51 Ma volcanic edifices discovered overlapping the remnant arc and intervening basins. The wide distribution of these edifices could mark the first arrival of upwelling mantle, which also mixed with local mid-oceanic-ridge basalt during contemporaneous West Philippine Basin spreading. These features are consistent with the extension and splitting of the Mesozoic arc terrane, driven by regional upwelling centered on the impact of the Oki-Daito mantle plume at 51 Ma.
ISSN:0091-7613
1943-2682
DOI:10.1130/G34525.1