Izu-Bonin arc

Several hydrothermal sites have been discovered on the seafloor of Izu-Bonin arc that is located at the eastern margin of the Philippine Sea plate (Fig. 2.32). This arc has been formed, related to the westward subduction of the Pacific plate (Fig. 2.32). Hydrothermal mineralization occurs both in back-arc depression and volcanic chain (Shichito-Iwojima Ridge). Hydrothermal venting and mineralizations are found... 

Fig. 2.32. Location and tectonic setting of Izu-Bonin arc. The solid circles mark the hydrothermal fields listed in Table 2.12. The broken lines delinate contours of 3000 m water depth (Ishibashi and Urabe, 1995).

Tsunogai, U., Ishibashi, J., Wakita, H., Gamo, T., Watanabe, K., Kajimura, T., Kanagawa, S. and Sakai, H. (1994) Peculiar features of Suiyo seamount hydrothermal fluids, Izu-Bonin arc Differences from subaerial volcanism. Earth Planet. Sci. Lett., 126, 289-301. 

As mentioned already in Chapter 2, submarine volcanism occurs not only at midoceanic ridges but also at subduction-related tectonic settings such as the Shikoku and Daito Basins, Farce Vela Basins, and Mariana Trough, Okinawa Trough and Izu Bonin Arc (e.g.. Wood et al., 1980 Dick, 1982 Delaney and Boyle, 1986). 

Takano, Y., Marumo, K., Ebashi, T., Gupta, L.P., Kawahata, H., Kobayashi, K., Yamagishi, A., and Kuwubara, T. 2005. In situ ore formation experiment Amino acids and amino sugars trapped in artificial chimneys on deep-sea hydrothermal systems at Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean. Bull. Chem. Soc. Jpn. 78 638-651. 

Boron-isotopic data also show the strong decrease in slab-derived boron across the width of the arc. Figure 5(a) documents the decline in 5 B across the Kurile and Izu-Bonin arcs, which follow cross-arc declines in boron abundances (Ishikawa and Nakamura, 1994 Ryan et al, 1995 Ishikawa and Tera, 1997). Ishikawa and Tera (1997) interpreted the cross-arc decline of boron isotopes in the Kuriles as a simple mixture of AOB-dominated slab boron with the mantle, which should be both boron depleted. 

The recent discovery of active hydrothermal vents in the summit calderas of andesitic volcanoes along a number of submarine volcanic arcs (e.g., Izu-Bonin arc, Mariana arc, Tonga-Kermadec arc Fig. 13.1) highlights the possible importance of... 

Takano, Y Kobayashi, K. Yamanaka, T. Marumo, K. Urabe, T. Amino adds in the 308 °C deep-sea hydrothermal system of the Suiyo Seamount, Izu-Bonin Arc, Pacific Ocean. Earth Planet Sd. Lett. 2004, 219, 147—153. 

---