Paleozoic ultramafic volcanic rocks of superplume origin in the accretionary complexes of Japan and its vicinity

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The results of this study are already published as many international journal papers. Ichiyama & Ishiwatari (2005) reported geological occurrence, chemistry and mineralogy of meimechite (Ti and HFSE-rich picrite) from the Jurassic Mum accretionary complex, and discussed its origin in the Permian superplume magmatism. Koizumi & Ishiwatari (2006) reported two contrasting occurrences and chemistry of greenstones in the Jurassic Tamba accretionary complex, namely basal nappe type and melange type, and attributed their origin to oceanic plateau and normal ocean float respectively Ichiyama, et al. (2006) reported chemical and isotopic composition of ferropicrites occurring in the accreted greenstones of the Tamba belt, and discussed their origin in relation to the Permian superplume magmatism in the oceanic area Ichiyama et at (2007) further reported olivine-spinifex basalt from the same area for the first time from the Phanerozoic, and discussed its geological significance in comparison wit … More h the similar Proterozoic rock occurring in the Pechenga area, Kola Peninsula and the results of spinifex reproduction experiments. Ichiyama et at (2008) divided basal nappe-type greenstones into 3 groups by distinct Ti concentration% and discussed their geological and chemical evolution in relation to the magmatism of a superplume's head and tail in the Permian oceanic area. Our related results include Ishiwatari, et al. (2006), which reported occurrence of adakite Sr the first time from the Izu-Bonin-Mariana arc, depicted distribution and chemical-mineralogical diversity of volcanic rocks, gabbros and peridotites, and presented a model that the Hahajima Seamount in the Bonin Forearc is a horst block composed of several ophiolitic thrust sheets that was uplifted due to collisional subduction of the Ogasawara Plateau. Yanagida et al. (2007) reported Mg-cummingtonite from metaperidotites dredged from the landward slope of the southern Mariana Trench, showed extremely wide mineral-chemical diversity and low equilibration temperatures of the mantle peridotites, and proposed that a forearc-backarc mantle section is exposed on the trench slope. Ishiwatari et at (2007) reported very rare, large-scale garnet peridotite-ultramafic complexes from the Pekulney Range, northeastern Russia. Less